Merge from origin/emacs-25

Merge from origin/emacs-25

784602b1050 (origin/emacs-25) ; Add release notice
3a34412caae (tag: emacs-25.2) Set Emacs version to 25.2 and update AU...
56a4461a48d ; Move stray item from admin/notes/repo to CONTRIBUTE
2b0d1118199 ; CONTRIBUTE: Remove stray header.
f2ab09ec60d Fix a typo in indexing the user manual
bc55a574235 * lisp/menu-bar.el (kill-this-buffer): Doc fix.  (Bug#26466)
a6d50401b4b Document 'line-pixel-height'
0c55cf43e61 * search.c (Fre_search_forward, Fre_search_backward): Imp...
c7ed57eaef4 Mention that processes start in default-directory (Bug#18...
856ec9ffa1f * src/xdisp.c (vmessage, message): Clarify commentary.
849a0aaa1c9 Belated fixes for admin.el's M-x make-manuals-dist
84938d79698 default-directory: Remark that it must be a directory name
3f0d047d2eb Delete confuse statement in manual
ee1bd94dd0c Improve packaging documentation
fb18bff91f0 Expand manual section on quitting windows
9a737079645 Fix docstring of dabbrev-abbrev-char-regexp
afe8849bac1 * doc/misc/cl.texi (Iteration Clauses): Clarify example (...
ada79442c07 ;* doc/misc/info.texi (Choose menu subtopic): Improve ind...
d38fd9229c0 Narrow scope of modification hook renabling in org-src fo...
e0e9db4c84a ; Spelling fix

# Conflicts:
#	README
#	etc/AUTHORS
#	etc/HISTORY
#	lisp/ldefs-boot.el