Merge from origin/emacs-26

Merge from origin/emacs-26

af1624f * lisp/net/shr.el (shr-browse-url): Doc fix.  (Bug#30957)
3a451bd ; * doc/emacs/msdos.texi: Fix wording of last change.
3bc1e2f Mention `key-description' as inverse of `kbd' (Bug#30942)
e50196e Document return value of pcase (Bug#30425)
8a2466f * doc/emacs/macos.texi: Tweak grammar and capitalization.
9db62bf Distinguish free from non-free OSes
ff49d86 * doc/emacs/misc.texi (Amusements): Avoid non-printing charac...
5bab671 Fix xrefs in pdf Emacs manual