Merge from origin/emacs-26

Merge from origin/emacs-26

90bea37 ; * etc/PROBLEMS: Fix fvwm version number in last commit
af82d1f * etc/PROBLEMS: Document stickyness problem with FVWM (Bug#31...
4a3aed2 Update Emacs Lisp Intro to match current behavior
21f2247 Merge branch 'emacs-26' of git.savannah.gnu.org:/srv/git/emac...
3257085 Fix previous commit
6d23525 Fix typos in several manuals (Bug#31610)
9188291 Add detailed documentation about lock files
e5471b2 Add commentary for subtle aspect of frame.el

Conflicts:
	doc/lispintro/emacs-lisp-intro.texi