Merge from origin/emacs-28

Merge from origin/emacs-28

1c3d107cb5 Fix "C-u C-x =" for SPC
7e33618bbc ; * src/fns.c (Frequire): Fix a typo in the doc string.  (...
6908309827 Doc fixes: don't refer to some obsolete items
dc3cb749f3 Remove obsolete cust-print from elisp index
9ffbbddf8e * admin/make-tarball.txt: Minor clarifications.
f5421104e9 Fix external image conversion on MS-Windows
6f22631a63 * doc/emacs/buffers.texi (Indirect Buffers): Mention modif...

# Conflicts:
#	doc/emacs/buffers.texi
#	lisp/emacs-lisp/nadvice.el
#	lisp/image/image-converter.el