Shorten over-wide docstrings in defcustoms

Shorten over-wide docstrings in defcustoms

* lisp/calc/calc.el (calc-embedded-announce-formula-alist)
(calc-embedded-open-formula, calc-embedded-close-formula)
(calc-matrix-mode):
* lisp/cedet/semantic/imenu.el (semantic-imenu-sort-bucket-function):
* lisp/emacs-lisp/find-func.el (find-feature-regexp):
* lisp/emulation/cua-base.el (cua-paste-pop-rotate-temporarily):
* lisp/emulation/viper-init.el (viper-fast-keyseq-timeout)
(viper-related-files-and-buffers-ring):
* lisp/emulation/viper-keym.el (viper-want-ctl-h-help):
* lisp/gnus/gnus-art.el (gnus-article-banner-alist):
* lisp/gnus/gnus-group.el (gnus-keep-same-level):
* lisp/gnus/gnus-score.el (gnus-adaptive-word-length-limit):
* lisp/gnus/gnus-sum.el (gnus-inhibit-user-auto-expire):
* lisp/gnus/gnus-uu.el (gnus-uu-ignore-files-by-type)
(gnus-uu-do-not-unpack-archives)
(gnus-uu-unmark-articles-not-decoded)
(gnus-uu-correct-stripped-uucode, gnus-uu-save-in-digest)
(gnus-uu-post-include-before-composing):
* lisp/gnus/gnus.el (gnus-use-long-file-name)
(gnus-install-group-spam-parameters):
* lisp/gnus/message.el (message-cite-style):
* lisp/gnus/nnmail.el
(nnmail-split-fancy-with-parent-ignore-groups)
(nnmail-cache-ignore-groups):
* lisp/ido.el (ido-rewrite-file-prompt-functions):
* lisp/mail/feedmail.el (feedmail-fiddle-plex-user-list)
(feedmail-spray-address-fiddle-plex-list):
* lisp/mh-e/mh-e.el (mh-annotate-msg-hook):
* lisp/net/imap.el (imap-process-connection-type):
* lisp/net/rcirc.el (rcirc-omit-threshold):
* lisp/net/tramp-sh.el (tramp-copy-size-limit):
* lisp/nxml/nxml-mode.el (nxml-default-buffer-file-coding-system):
* lisp/obsolete/landmark.el (landmark-max-stall-time):
* lisp/obsolete/tls.el (tls-checktrust):
* lisp/org/org-indent.el
(org-indent-mode-turns-off-org-adapt-indentation)
(org-indent-mode-turns-on-hiding-stars):
* lisp/org/org-protocol.el (org-protocol-project-alist):
* lisp/progmodes/cc-vars.el (c-doc-comment-style):
* lisp/progmodes/cperl-mode.el (cperl-indent-subs-specially):
* lisp/progmodes/flymake-proc.el (flymake-proc-allowed-file-name-masks):
* lisp/progmodes/hideif.el (hide-ifdef-expand-reinclusion-protection):
* lisp/simple.el (minibuffer-history-case-insensitive-variables):
* lisp/tab-bar.el (tab-bar-close-last-tab-choice):
* lisp/textmodes/reftex-vars.el
(reftex-special-environment-functions):
* lisp/vc/ediff-init.el (ediff-startup-hook, ediff-cleanup-hook)
(ediff-metachars):
* lisp/vc/ediff-merg.el (ediff-show-clashes-only):
* lisp/vc/ediff-mult.el (ediff-default-filtering-regexp): Shorten doc
strings to not exceed 80-column limits.  (Bug#44858)