Merge from origin/emacs-29

Merge from origin/emacs-29

a4828155d8f ; * doc/lispintro/emacs-lisp-intro.texi (nthcdr): Whitesp...
df1a9e42ba4 Document :box attribute caveats when used on display strings
ca17bc8dd0b Improve documentation of 'movemail'
d47aa33bcdb Replace incorrect link in Rmail chapter of Emacs manual
35138b90dd2 ; * doc/lispref/parsing.texi (Parsing Program Source): Im...
3dd09516c9a ; Improve documentation of 'set-fontset-font'
042b58b5ff4 ; * doc/emacs/search.texi (Word Search): Add index entry.
60b1768dc50 ; * src/window.c (Fwindow_scroll_bars): Doc fix.