Add test for file-name-base

* test/lisp/files-tests.el (files-tests-file-name-base): New test.

; * lisp/image-dired.el: Move obsolete things to "Obsolete" section

image-dired: Improve mouse behaviour

* lisp/image-dired.el (image-dired-thumbnail-mode-map): Improve mouse
behaviour: ignore dragging, as it currently doesn't do anything
useful, and make all clicks just select the thumbnail.
(image-dired-mouse-display-image)
(image-dired-mouse-select-thumbnail): Move point to closest image
after clicking in buffer.

image-dired: Don't ding at beginning or end of buffer

* lisp/image-dired.el
(image-dired--display-thumb-properties-fun): New defun.
(image-dired-forward-image, image-dired-backward-image): Don't ding
when moving past first or last image; instead show a message, wait a
second and then show image properties.

image-dired: Add new commands for beginning/end of buffer

* lisp/image-dired.el (image-dired-beginning-of-buffer)
(image-dired-end-of-buffer): New commands.
(image-dired-thumbnail-mode-map): Bind new beginning of buffer command
to '<' and 'M-<', and end of buffer command to '>' and 'M->'.

Add new function image-at-point-p

* lisp/image.el (image-at-point-p): New defun.
* doc/lispref/display.texi (Showing Images): Document above new defun.

image-dired: Use an evenly spaced grid for thumbnails

* lisp/image-dired.el (image-dired-line-up): Use an evenly spaced
grid for thumbnails, even if image sizes differ.

; * lisp/image-dired.el (image-dired-cmd-pngnq-options): Fix :version.

image-dired: Use example.org in examples

* lisp/image-dired.el (image-dired-gallery-image-root-url)
(image-dired-gallery-thumb-image-root-url): Use example.org to be
RFC 2606 compliant.

image-dired: Increase number of asynch thumbnail generation jobs

* lisp/image-dired.el (image-dired-queue-active-limit): Increase the
number of asynchronous thumbnail generation jobs to a maximum of 4 or
processor count divided by 2.  This makes thumbnail generation around
30 % faster when benchmarking this on my machine (8 cores/4 jobs).

(image-dired-debug): New defvar.
(image-dired-debug-message): New defun.

(image-dired--generate-thumbs-start): New defvar.
(image-dired-create-thumb-1, image-dired-display-thumbs): Display time
spent on thumbnail generation if 'image-dired-debug' is non-nil.

CC Mode: minor amendments more accurately to handle virtual semicolons, etc.

* lisp/progmodes/cc-engine.el (c-laomib-loop): Check for a virtual semicolon
as well as a ;.
(c-guess-basic-syntax): CASE 5D - Use c-crosses-statement-barrier-p to check
whether we've gone back past a virtual semicolon.

* lisp/progmodes/cc-engine.el (c-fontify-new-found-type): Declare near BO File

* test/infra/gitlab-ci.yml (build-image-inotify): Increase timeout.

(test-native-comp-speed0): Adapt make_params.

* lisp/progmodes/xref.el (xref-pop-marker-stack): Don't obsolete.

; * test/lisp/progmodes/elisp-mode-tests.el: repair test failure

The test used an internal variable that has been renamed; use the new
name.  (Any variable would do here.)

Rename `xref-pop-marker-stack` to `xref-go-back` (bug#38797)

It is the natural name after the addition of `xref-go-forward`.
The old name is retained as an alias.

* lisp/progmodes/xref.el (xref-pop-marker-stack): Rename.
(xref-go-forward, xref-quit-and-pop-marker-stack)
(xref-find-definitions):
* lisp/menu-bar.el (menu-bar-goto-menu):
* lisp/progmodes/etags.el (find-tag-marker-ring, pop-tag-mark):
* lisp/progmodes/prog-mode.el (prog-context-menu):
* doc/emacs/maintaining.texi (Looking Up Identifiers):
* etc/NEWS:
Use the new name.

; * lisp/menu-bar.el (menu-bar-goto-menu): Adjust new item position

IMAP search should only use charset utf-8 with multibyte strings

Background: Exchange servers cannot accept "charset utf-8" search
strings. The code originally set that charset for any server with
literal+ capability, borking all searches on an Exchange server. This
code only sets utf-8 for multibyte search strings in particular, which
would be borken for Exchange anyway.

* lisp/gnus/gnus-search.el (gnus-search-imap-search-command): Ensure
we're only doing the literal+ dance for multibyte strings (multibyte
strings will have had newlines inserted in an earlier step).

Merge from origin/emacs-28

a2c17e115e (origin/emacs-28) Merge branch 'emacs-28' of git.savannah....
fde56eeb76 Revert "Fix a typo in emacs-lisp-intro.texi"
4779d3ba19 * doc/lispref/functions.texi (Mapping Functions): Use #' w...
85ea3f7f47 Fix issue with interpreting ANSI codes in eshell
50f9436146 image-dired: Doc fix to better explain thumbnail generation
bb475e10b9 Clarify two image-dired docstrings
f5b4bb4a6f Fix flymake example backend conditions in the manual
0771d8939a * etc/PROBLEMS: Mention problems with regexp matcher.  (Bu...
ee579033b9 * test/lisp/repeat-tests.el: New file.
7385a7667f * lisp/tab-bar.el (tab-bar-move-repeat-map): Fix alias bin...
56caf1c9b8 Use restrictive umask when creating image-dired data
3b5de7f991 ; lisp/transient.el: Revert some misguided stylistic fixes.

; Merge from origin/emacs-28

The following commit was skipped:

3f763898aa Fix compilation errors with MinGW64 GCC 11

Merge from origin/emacs-28

817c929eda Doc fix for concat
3eca2ad2a1 * lisp/image-dired.el (image-dired-external-viewer): Suppo...

* doc/misc/cc-mode.texi (Font Locking): Fix menu.

Merge branch 'emacs-28' of git.savannah.gnu.org:/srv/git/emacs into emacs-28

Revert "Fix a typo in emacs-lisp-intro.texi"

This reverts commit 98eb6d783a482cd7ebca7ec656b0775b82c68e57.
I've consulted with Richard Stallman about this, and he says
that the original wording, "kinds of atom", is both correct
and more elegant writing.  So I'm restoring the original text.
* doc/lispintro/emacs-lisp-intro.texi (Lisp Atoms): Undo the
fix of a "typo" that wasn't a typo.  (Bug#51271)

Add the "always" zsh builtin to zsh mode

* lisp/progmodes/sh-script.el (sh-builtins): Add the "always" zsh
keyword (bug#51387).

Add xref forward history (bug#38797)

Make it possible to go forward as well as back in the Xref history.
The new `xref-go-forward` is bound to `C-M-,`.

* lisp/progmodes/etags.el (find-tag-marker-ring-length): Update.
(tags-location-ring-length): New.
(find-tag-marker-ring): Keep as dummy.
(tags-location-ring, tags-reset-tags-tables):
Use `tags-location-ring-length` instead of `xref-marker-ring-length`.
* lisp/progmodes/xref.el (xref-marker-ring-length, xref-marker-ring)
(xref-set-marker-ring-length):
Make obsolete.
(xref--history, xref-go-forward, xref-forward-history-empty-p): New.
(xref-push-marker-stack, xref-pop-marker-stack)
(xref-clear-marker-stack, xref-marker-stack-empty-p):
Use `xref--history`.
* lisp/menu-bar.el (menu-bar-goto-menu): Add Forward entry.
* doc/emacs/maintaining.texi (Looking Up Identifiers): Document.
* etc/NEWS: Announce.

Allow viewing .heic images via image-convert

* lisp/files.el (auto-mode-alist): Support the Apple .heic/HEIF
image format (bug#51381).

Change the with-delayed-message syntax to allow future extensibility

* doc/lispref/display.texi (Progress): Document it.
* lisp/subr.el (with-delayed-message): Change the syntax to allow
future extensibility.

* lisp/net/eww.el (eww-display-html): Use it.

Heed the EMACS_IGNORE_TIMERFD environment variable

* src/emacs.c (main): Call init_atimer after setting up the
environment so that the EMACS_IGNORE_TIMERFD environment variable
is actually heeded.

* doc/lispref/functions.texi (Mapping Functions): Use #' when mapping.

Fix issue with interpreting ANSI codes in eshell

* lisp/eshell/esh-mode.el (eshell-mode): Make window point advance on
insertion.
(eshell-output-filter): Don't use insert-before-markers (bug#45380).

; Fix mangled indentation in 'display-buffer' doc-string

Allow 'display-buffer' to set up body size of chosen window (Bug#17065)

* doc/lispref/windows.texi (Buffer Display Action Alists):
Describe new possible values for 'window-height', 'window-width'
and 'window-size' action alist entries.
* lisp/window.el (window--display-buffer): Handle new values for
'window-height', 'window-width' and 'window-size' ALIST entries.
(display-buffer): Update doc-string for new values of some
action alist entries.
* etc/NEWS: Mention new values of some action alist entries.

New function xdg-state-home

* lisp/xdg.el (xdg-state-home): New function.  This returns
$XDG_STATE_HOME according to the XDG Base Directory Specification
version 0.8 (08th May 2021).

image-dired: Improve XDG compliance

* lisp/image-dired.el (xdg): Require.
(image-dired-main-image-directory): Prefer XDG_PICTURES_HOME.
(image-dired-thumb-name): Simplify by using 'xdg-cache-home'.

Double value of image-dired-show-all-from-dir-max-files

* lisp/image-dired.el (image-dired-show-all-from-dir-max-files):
Double the amount of files in directory before prompting.  This could
be even higher, as the thumbnails are generated asynchronously and are
small by default.

image-dired: Doc fix to better explain thumbnail generation

* doc/emacs/dired.texi (Image-Dired): Improve description by
explaining that the generation of thumbnails is asynchronous.

image-dired: Add support for GraphicsMagick

* lisp/image-dired.el (image-dired-cmd-create-thumbnail-program)
(image-dired-cmd-create-thumbnail-options)
(image-dired-cmd-create-temp-image-program)
(image-dired-cmd-create-temp-image-options)
(image-dired-cmd-rotate-thumbnail-program)
(image-dired-cmd-rotate-thumbnail-options): Add support for the
GraphicsMagick command line tool ("gm convert", "gm mogrify").

Fix issues with type casting in delayed message functions

* src/eval.c (with_delayed_message_display)
(with_delayed_message_cancel, Ffuncall_with_delayed_message): Fix
some type confusion.

Support new Thumbnail Managing Standard sizes in image-dired

* lisp/image-dired.el
(image-dired--thumbnail-managing-standard-sizes): New defconst.
(image-dired-thumbnail-storage)
(image-dired-thumb-name, image-dired-insert-thumbnail)
(image-dired-thumb-size, image-dired-create-thumb-1): Support larger
thumbnail sizes mandated by new version of the Thumbnail Managing
Standard (December 2020, Version 0.9.0).

Clarify two image-dired docstrings

* lisp/image-dired.el (image-dired-dir): Doc fix; clarify that
thumbnails will be saved in "$XDG_CACHE_HOME/thumbnails", as per the
Thumbnail Managing Standard.
(image-dired-thumb-size): Doc fix; clarify that this option will be
ignored when using the Thumbnail Managing Standard.

Fix flymake example backend conditions in the manual

* doc/misc/flymake.texi (An annotated example backend): Also react
to `signal' process statuses (bug#51380).

* etc/PROBLEMS: Mention problems with regexp matcher.  (Bug#18577)

Use SHA1 when creating thumbnail file name

* lisp/image-dired.el (image-dired-thumb-name): Improve docstring.
Use SHA1 for hashing when creating file name.  SHA1 is slightly faster
than MD5, and has a few more bits.

Remove debugging in with_delayed_message_display

* src/eval.c (with_delayed_message_display): Remove debugging.

Display a message if HMTL rendering takes a long time

* lisp/net/eww.el (eww-display-html): Display a message if HTML
rendering takes a long time (bug#19776).

Add new macro `with-delayed-message'

* doc/lispref/display.texi (Progress): Document it.
* lisp/subr.el (with-delayed-message): New macro.

* src/eval.c (with_delayed_message_display)
(with_delayed_message_cancel): Helper functions.
(Ffuncall_with_delayed_message): New function (bug#19776).

CC Mode: Fontify "found types" which are recognized after being first scanned

This aims to fix the scenario where on jit-lock's first scan of a type, it is
not recognized as such, and only later does this happen.  The fontification of
such found types is now done by background scanning in short time slices
immediately after initialising the mode.

* lisp/progmodes/cc-engine.el (c-add-type-1): New function.
(c-add-type): Extract c-add-type-1 from it, and reformulate the mechanism for
protecting c-found-types from excessive partial identifiers.

* lisp/progmodes/cc-fonts.el (c-font-lock-complex-decl-prepare): Remove the
code which cleared c-found-types on fontification at BOB.
(c-find-types-background): New function, based on c-font-lock-declarations).
(c-type-finder-timer-func): New function.
(c-re-redisplay-timer): New variable.
(c-force-redisplay, c-fontify-new-found-type): New functions.

* lisp/progmodes/cc-mode.el (c-type-finder-timer, c-inhibit-type-finder): New
variables.
(c-leave-cc-mode-mode): Nullify c-post-command-hook, c-post-gc-hook, and
c-type-finder-timer when the last CC Mode buffer of a session is killed.
(c-type-finder-pos): New variable.
(c-basic-common-init): Initialize/Install c-post-command, c-c-type-finder-pos,
c-type-finder-timer, and c-post-gc-hook.
(c-new-id-start, c-new-id-end, c-new-id-is-type): New variables.
(c-update-new-id): New function.
(c-post-command): New post command hook function, used for checking moving
away from partially typed identifiers, and making them full identifiers.
(c-post-gc-hook): New hook to prevent CC Mode activity immediately following
GC, thus allowing keyboard/mouse input to be registered.
(c-before-change): Add code to clear c-found-types on a buffer change at BOB.
(c-after-change): Call c-update-new-id to keep track of partially typed
identifiers.

* doc/misc/cc-mode.texi (Found Types): New @section in the @Chapter Font
Locking.

* lisp/progmodes/cc-vars.el (c-type-finder-time-slot)
(c-type-finder-repeat-time, c-type-finder-chunk-size): New customizable
options.

* test/lisp/repeat-tests.el: New file.

* lisp/tab-bar.el (tab-bar-move-repeat-map): Fix alias binding of tab-move.

(tab-bar-move-tab-backward): Put 'repeat-map' symbol property.

Fix mouse buttons in dired--make-directory-clickable

* lisp/dired.el (dired--make-directory-clickable): Adjust mouse
clicks to conform to our standards.

Use restrictive umask when creating image-dired data

* lisp/image-dired.el (image-dired-dir)
(image-dired-sane-db-file): Create thumbnail directory and
.image-dired_db with umask 077.  This avoids creating world readable
copies of private data, and is in fact mandated by the Thumbnail
Managing Standard that we aim to support.

; lisp/transient.el: Revert some misguided stylistic fixes.

These aren't actual modes.  Set checkdoc-symbol-words to avoid
false-positives.  The first line of doc-strings of methods do
not need to end with period.

Don't unhide first thread if entering without selecting article

* lisp/gnus/gnus-sum.el (gnus-summary-first-unread-subject)
(gnus-summary-first-unseen-subject)
(gnus-summary-first-unseen-or-unread-subject): Use it.
(gnus-summary--goto-and-possibly-unhide): New function -- don't
unhide the first thread unless necessary (bug#51344).

Improve documentation of image-dired thumbnails

* lisp/image-dired.el: Fix documentation on thumbnail file format to
correctly say that it can be either PNG or JPEG; not just JPEG.  Also
fix inconsistent formatting in comments.
* lisp/image-dired.el (image-dired-thumbnail-storage): Improve
docstring.

Add support for pngquant to image-dired

* lisp/image-dired.el (image-dired-cmd-pngnq-program)
(image-dired-cmd-pngnq-options): Add support for pngquant.
Prefer, in this order: pngquant, pngnq-s9, pngnq-s for reasons of
speed and how actively maintained the projects seem to be.

Fix compilation errors with MinGW64 GCC 11

* lib-src/ntlib.c (IS_DIRECTORY_SEP): Remove redundant macro.

* lib-src/ntlib.c (DEFER_MS_W32_H):
* nt/addpm.c (DEFER_MS_W32_H):
* nt/cmdproxy.c (DEFER_MS_W32_H):
* nt/ddeclient.c (DEFER_MS_W32_H):
* nt/preprep.c (DEFER_MS_W32_H):
* nt/runemacs.c (DEFER_MS_W32_H): Fix a typo.
* nt/Makefile.in (BASE_CFLAGS): Add -I switches to pick up
config.h and lib/attribute.h.

Include <config.h> first in MS-Windows source

Fix compilation errors with MinGW64 GCC 11

* lib-src/ntlib.c (_GL_ATTRIBUTE_MALLOC)
(_GL_ATTRIBUTE_DEALLOC_FREE): Define to avoid compilation errors
with MinGW64 GCC 11.  Suggested by Andy Moreton
<andrewjmoreton@gmail.com>.  Do not merge to master.

Fix define-erc-response-handler indentation

* lisp/erc/erc-backend.el (define-erc-response-handler): Add
proper indentation.

; Unbreak creating thumbnails in image-dired

* lisp/image-dired.el (image-dired-insert-thumbnail): Unbreak
creating thumbnails after my previous commit.

; * etc/NEWS: Fix typos.

Add new option help-link-key-to-documentation

* lisp/help.el (help-link-key-to-documentation): New user option.
(substitute-command-keys): Add a link from keys to the command they
are bound to, if the above new option is non-nil.  (Bug#8951)
* etc/NEWS: Announce the new option.

Make dired directory components clickable

* lisp/dired.el (dired-readin): Use it.

* lisp/dired.el (dired-make-directory-clickable): New user option.

* lisp/dired.el (dired--make-directory-clickable): New function
(bug#21973).

Don't use obsolete variable `find-tag-marker-ring`

* lisp/progmodes/js.el (js-find-symbol):
* lisp/progmodes/octave.el (octave-find-definition):
Call `xref-push-marker-stack` instead of manipulating the obsolete
variable `find-tag-marker-ring`.

Tweak bug-reference-tests

* test/lisp/progmodes/bug-reference-tests.el: Tweak tests a bit.

Clean up duplicated setting in scheme-mode-variables

* lisp/progmodes/scheme.el (scheme-mode-variables): Remove
repeated setting.

Allow matching non-.git URLs in bug-reference

* lisp/progmodes/bug-reference.el
(bug-reference--build-forge-setup-entry): Allow matching non-.git
URLs, with and without slashes (bug#51316).

Doc fix for concat

* src/fns.c (Fconcat): Note that composition values may not remain eq
in return value of concat.  (Bug#48740)

Don't hard-code image-dired thumbnail type

* lisp/image-dired.el (image-dired-insert-thumbnail): Detect thumbnail
image type instead of hard-coding it.

* lisp/image-dired.el (image-dired-external-viewer): Support feh.

Expand tests for image-type-from-file-header

* test/lisp/image-tests.el (image-tests--files): New defconst.
(image-tests--type-from-file-header): New defun.
(image-type-from-file-header-test/jpeg)
(image-type-from-file-header-test/pbm)
(image-type-from-file-header-test/png)
(image-type-from-file-header-test/svg)
(image-type-from-file-header-test/tiff)
(image-type-from-file-header-test/webp)
(image-type-from-file-header-test/xbm)
(image-type-from-file-header-test/xpm): New tests.
(image-type-from-file-header-test): Delete test.

Add tests for gif to src/image-tests.el

* test/src/image-tests.el (image-tests--images): Rename from
image-tests-files.  Add gif.
(image-tests-image-size/gif)
(image-tests-image-mask-p/gif)
(image-tests-image-metadata/gif): New tests.
* test/data/image/black.gif: New file.

Merge from origin/emacs-28

c7f53824a8 (origin/emacs-28) Update publicsuffix.txt from upstream
9a50f760e9 ; * doc/lispref/modes.texi (Hooks): Clarify wording.  (Bug...
e154fd9119 Refer to the info node on keymaps in map-keymap docstring
4fd5c8df67 Clarify abnormal hook documentation
6fa5206770 Update to Org 9.5-59-g52e6f1
39413a45bf ; * doc/lispref/functions.texi (Calling Functions): Fix la...
43914ab01f Improve documentation of cl-reduce
ef37a86cac Improve documentation of apply-partially
1e8be48738 Fix typos
8c5fbd712b Revert commit 225ca617b7, and apply another fix
cdbd03345d Fix documentation of posn-at-x-y
598732c899 ; * src/vm-limit.c (get_lim_data): Fix a typo.  (Bug#18238)
efdffd86c5 ; * etc/refcards/README: Prefer HTTPS in link.

# Conflicts:
# etc/NEWS

Update publicsuffix.txt from upstream

* etc/publicsuffix.txt: Update from
https://publicsuffix.org/list/public_suffix_list.dat
dated 2021-10-16 16:33:47 GMT.

; * doc/lispref/modes.texi (Hooks): Clarify wording.  (Bug#34588)

Make dired-x-guess-file-name-at-point obsolete

* lisp/dired-x.el (dired-x-guess-file-name-at-point): Make
obsolete in favour of 'thing-at-point'.
(dired-x-read-filename-at-point): Use 'thing-at-point' instead of
above obsolete function.

Refer to the info node on keymaps in map-keymap docstring

* src/keymap.c (Fmap_keymap): Doc fix; add a reference to the Info
node '(elisp) Keymaps'.  (Bug#30958)

Clarify abnormal hook documentation

* doc/lispref/hooks.texi (Standard Hooks):
* doc/lispref/modes.texi (Hooks): Clarify wording of "abnormal
hook" documentation.  (Bug#34588)

Update to Org 9.5-59-g52e6f1

; * doc/lispref/functions.texi (Calling Functions): Fix last change.

Improve documentation of cl-reduce

* doc/misc/cl.texi (Mapping over Sequences): Change the
explanation of 'cl-reduce' so you don't need to have a major in
mathematics to understand it.  (Bug#24014)

Improve documentation of apply-partially

* doc/lispref/functions.texi (Calling Functions): Improve
documentation of 'apply-partially' to be slightly more clear with
regards to function arity.  (Bug#17623)

Check for image library in image-dired-tests.el

* test/lisp/image-dired-tests.el
(image-dired-tests-get-exif-file-name): Check for jpeg library.

Support :company-deprecated completion property

* lisp/progmodes/elisp-mode.el (elisp--company-deprecated):
New function.
(elisp-completion-at-point): Use it.

Fix typos

* doc/emacs/cmdargs.texi:
* etc/DEBUG:
* etc/NEWS: Fix typos.

Revert commit 225ca617b7, and apply another fix

* lisp/minibuffer.el (read-file-name-default): Revert commit
225ca617b7.  (Bug#50976).

* lisp/shell.el (shell): Remove volume letter for remote shell
file name.  (Bug#49229)

* test/infra/gitlab-ci.yml (variables, default): Increase timeout to 4 hours.

Revert "CC Mode: Fontify "found types" which are recognized after being ..."

This reverts commit 51719617eb19833056618ebac403cdcaf711551a.  The commit
caused a hang at start-up with a big desktop.

Fix documentation of posn-at-x-y

* doc/lispref/commands.texi (Accessing Mouse): Fix documentation of
'posn-at-x-y' to match docstring.  (Bug#15783)

Partially remove exiftool dependency from image-dired.el

* lisp/image-dired.el (exif): Require.
(image-dired-cmd-read-exif-data-program)
(image-dired-cmd-read-exif-data-options)
(image-dired-get-exif-data): Make obsolete in favour of using
exif.el.  This removes a dependency on external exiftool for some
operations.
(image-dired-get-exif-file-name)
(image-dired-thumbnail-set-image-description): Use exif.el
functions instead of exiftool.
* lisp/image/exif.el (exif-tag-alist): Add description and
copyright fields.
* test/lisp/image-dired-tests.el: New file.

; * src/vm-limit.c (get_lim_data): Fix a typo.  (Bug#18238)

Add new function exif-field

* test/lisp/image/exif-tests.el (exif-elem): Move function from here...
* lisp/image/exif.el (exif-field): ...to here, and rename.
(exif-orientation):
* test/lisp/image/exif-tests.el (test-exif-parse)
(test-exif-parse-short): Use above new function.

Add links to commentary reached with finder-list-keywords

* lisp/finder.el (finder-goto-xref): Move from here...
* lisp/emacs-lisp/package.el (package--finder-goto-xref): ...to
here.  Make the old name into an obsolete function alias.
(package--finder-xref): New button type.
(package--describe-add-library-links): Factor out new function...
* lisp/finder.el (finder-commentary): ...from here.
(describe-package-1): Call above new function.  This fixes an
issue where commentaries reached via 'finder-list-keywords' did
not have links.  (Bug#10814)

* src/image.c (webp_load): Fix thinkos.

; * etc/refcards/README: Prefer HTTPS in link.

CC Mode: Fontify "found types" which are recognized after being first scanned

This aims to fix the scenario where on jit-lock's first scan of a type, it is
not recognized as such, and only later does this happen.  The fontification of
such found types is now done by background scanning in short time slices
immediately after initialising the mode.

* lisp/progmodes/cc-engine.el (c-add-type-1): New function.
(c-add-type): Extract c-add-type-1 from it, and reformulate the mechanism for
protecting c-found-types from excessive partial identifiers.

* lisp/progmodes/cc-fonts.el (c-font-lock-complex-decl-prepare): Remove the
code which cleared c-found-types on fontification at BOB.
(c-find-types-background): New function, based on c-font-lock-declarations).
(c-types-finder-timer-func): New function.
(c-re-redisplay-timer): New variable.
(c-force-redisplay, c-fontify-new-found-type): New functions.

* lisp/progmodes/cc-mode.el (c-type-finder-timer): New variable.
(c-leave-cc-mode-mode): Nullify c-post-command-hook and c-type-finder-timer
when the last CC Mode buffer of a session is killed.
(c-type-finder-pos): New variable.
(c-basic-common-init): Initialize c-type-finder-pos and c-type-finder-timer.
(c-new-id-start, c-new-id-end, c-new-id-is-type): New variables.
(c-update-new-id): New function.
(c-post-command): New post command hook function, used for checking moving
away from partially typed identifiers, and making them full identifiers.
(c-before-change): Add code to clear c-found-types on a buffer change at BOB.
(c-after-change): Call c-update-new-id to keep track of partially typed
identifiers.

* doc/misc/cc-mode.texi (Found Types): New @section in the @Chapter Font
Locking.

* lisp/progmodes/cc-vars.el (c-type-finder-time-slot)
(c-type-finder-repeat-time, c-type-finder-chunk-size): New customizable
options.

Merge from origin/emacs-28

b0d64be0bc (origin/emacs-28) Improve some NEWS entries
7fde84e881 Improve documentation of syntax-ppss-context slightly
5ecbed01b2 ; * test/lisp/mh-e/mh-utils-tests.el: Update macro declara...
168665da59 Move some xwidget entries
efde024361 time-stamp-tests: improvements to test macros
06c944cff1 Fix rfc6068-parse-mailto-url autoload
9b6b5e37ef Regexp-quote github domains in bug-reference
1f6cdeb12c Ensure valid end/beginning lines in message-mark-inserted-...
9b46150ab0 * etc/NEWS: Improve 'repeat-mode' entry.
9c37b812da ; * lisp/repeat.el (repeat-mode): Fix docstring typo.
caf87d80fa * lisp/repeat.el (repeat-keep-prefix): Expand description.
24083c8d13 * lisp/net/eww.el (eww-retrieve-command): Add :tag.
cf7d8fb1d7 Add description of cards to etc/refcards/README
d2849cc645 Fix 'calculate-lisp-indent' when "[" starts containing sex...
2a0a368ddc Fix typo in doc/emacs/anti.texi
9529e1d2fb Update doc of Edebug specification for macros
5bc522b4f4 ; * lisp/simple.el (kill-region): A better fix for bug#51320.
ee6bdd6eef Fix non-interactive behavior of 'kill-region'
2b7655ca0e ; More accurate doc string for 'tab-bar-format'
2841e26744 * test/lisp/dabbrev-tests.el: Use 'kbd' for readable keys.
1cdb4d2077 * lisp/menu-bar.el (menu-bar-keymap): Add optional arg KEY...

# Conflicts:
# etc/NEWS
# lisp/progmodes/bug-reference.el

Improve some NEWS entries

* etc/NEWS: Improve some NEWS entries.

Improve documentation of syntax-ppss-context slightly

* doc/lispref/syntax.texi (Parser State): Document all possible return
values from 'syntax-ppss-context'.