Merge from origin/emacs-27

bd7b681dc4 (origin/emacs-27) Tiny texinfo markup fixes
d0dd0e0612 ; Fix more @var/@code mixups in Elisp manual
313dc0439e ; Fix another format-spec typo in the Elisp manual
9d7fd78421 Make next-error behavior a bit more flexible
0691d25295 * etc/NEWS.25: Belatedly announce upcase-dwim and downcase...
df91c94ca8 Fix access to single-byte characters in buffer text

diff --cc doc/lispref/edebug.texi
Simple merge

diff --cc doc/lispref/files.texi
Simple merge

diff --cc doc/lispref/loading.texi
Simple merge

diff --cc doc/lispref/os.texi
Simple merge

diff --cc doc/lispref/text.texi
Simple merge

diff --cc lisp/simple.el
Simple merge

diff --cc src/cmds.c
Simple merge

diff --cc src/xdisp.c
Simple merge