This patch should not change behavior.  It typically omits backslashes
where they are redundant (e.g., in the string literal "^\$").
In a few places, insert backslashes where they make regular
expressions clearer: e.g., replace "^\*" (equivalent to "^*") with
"^\\*", which has the same effect as a regular expression.
Also, use ‘\ %’ instead of ‘\%’ when avoiding confusion with SCCS IDs,
and similarly use ‘\ $’ instead of ‘\$’ when avoiding confusion with
RCS IDs, as that makes it clearer that the backslash is intended.

Prefer directed to neutral quotes in docstings and diagnostics.
In docstrings, escape apostrophes that would otherwise be translated
to curved quotes using the newer, simpler rules.
* admin/unidata/unidata-gen.el (unidata-gen-table):
* lisp/align.el (align-region):
* lisp/allout.el (allout-mode, allout-solicit-alternate-bullet):
* lisp/bookmark.el (bookmark-default-annotation-text):
* lisp/calc/calc-aent.el (math-read-if, math-read-factor):
* lisp/calc/calc-lang.el (math-read-giac-subscr)
(math-read-math-subscr):
* lisp/calc/calc-misc.el (report-calc-bug):
* lisp/calc/calc-prog.el (calc-fix-token-name)
(calc-read-parse-table-part):
* lisp/cedet/ede/pmake.el (ede-proj-makefile-insert-dist-rules):
* lisp/cedet/semantic/complete.el (semantic-displayor-show-request):
* lisp/dabbrev.el (dabbrev-expand):
* lisp/emacs-lisp/checkdoc.el (checkdoc-this-string-valid-engine):
* lisp/emacs-lisp/elint.el (elint-get-top-forms):
* lisp/emacs-lisp/lisp-mnt.el (lm-verify):
* lisp/emulation/viper-cmd.el (viper-toggle-search-style):
* lisp/erc/erc-button.el (erc-nick-popup):
* lisp/erc/erc.el (erc-cmd-LOAD, erc-handle-login):
* lisp/eshell/em-dirs.el (eshell/cd):
* lisp/eshell/em-glob.el (eshell-glob-regexp):
* lisp/eshell/em-pred.el (eshell-parse-modifiers):
* lisp/eshell/esh-arg.el (eshell-parse-arguments):
* lisp/eshell/esh-opt.el (eshell-show-usage):
* lisp/files-x.el (modify-file-local-variable):
* lisp/filesets.el (filesets-add-buffer, filesets-remove-buffer)
(filesets-update-pre010505):
* lisp/find-cmd.el (find-generic, find-to-string):
* lisp/gnus/auth-source.el (auth-source-netrc-parse-entries):
* lisp/gnus/gnus-agent.el (gnus-agent-check-overview-buffer)
(gnus-agent-fetch-headers):
* lisp/gnus/gnus-int.el (gnus-start-news-server):
* lisp/gnus/gnus-registry.el:
(gnus-registry--split-fancy-with-parent-internal):
* lisp/gnus/gnus-score.el (gnus-summary-increase-score):
* lisp/gnus/gnus-start.el (gnus-convert-old-newsrc):
* lisp/gnus/gnus-topic.el (gnus-topic-rename):
* lisp/gnus/legacy-gnus-agent.el (gnus-agent-unlist-expire-days):
* lisp/gnus/nnmairix.el (nnmairix-widget-create-query):
* lisp/gnus/spam.el (spam-check-blackholes):
* lisp/mail/feedmail.el (feedmail-run-the-queue):
* lisp/mpc.el (mpc-playlist-rename):
* lisp/net/ange-ftp.el (ange-ftp-shell-command):
* lisp/net/mairix.el (mairix-widget-create-query):
* lisp/net/tramp-cache.el:
* lisp/obsolete/otodo-mode.el (todo-more-important-p):
* lisp/obsolete/pgg-gpg.el (pgg-gpg-process-region):
* lisp/obsolete/pgg-pgp.el (pgg-pgp-process-region):
* lisp/obsolete/pgg-pgp5.el (pgg-pgp5-process-region):
* lisp/org/ob-core.el (org-babel-goto-named-src-block)
(org-babel-goto-named-result):
* lisp/org/ob-fortran.el (org-babel-fortran-ensure-main-wrap):
* lisp/org/ob-ref.el (org-babel-ref-resolve):
* lisp/org/org-agenda.el (org-agenda-prepare):
* lisp/org/org-bibtex.el (org-bibtex-fields):
* lisp/org/org-clock.el (org-clock-notify-once-if-expired)
(org-clock-resolve):
* lisp/org/org-feed.el (org-feed-parse-atom-entry):
* lisp/org/org-habit.el (org-habit-parse-todo):
* lisp/org/org-mouse.el (org-mouse-popup-global-menu)
(org-mouse-context-menu):
* lisp/org/org-table.el (org-table-edit-formulas):
* lisp/org/ox.el (org-export-async-start):
* lisp/play/dunnet.el (dun-score, dun-help, dun-endgame-question)
(dun-rooms, dun-endgame-questions):
* lisp/progmodes/ada-mode.el (ada-goto-matching-start):
* lisp/progmodes/ada-xref.el (ada-find-executable):
* lisp/progmodes/antlr-mode.el (antlr-options-alists):
* lisp/progmodes/flymake.el (flymake-parse-err-lines)
(flymake-start-syntax-check-process):
* lisp/progmodes/python.el (python-define-auxiliary-skeleton):
* lisp/progmodes/sql.el (sql-comint):
* lisp/progmodes/verilog-mode.el (verilog-load-file-at-point):
* lisp/server.el (server-get-auth-key):
* lisp/subr.el (version-to-list):
* lisp/textmodes/reftex-ref.el (reftex-label):
* lisp/textmodes/reftex-toc.el (reftex-toc-rename-label):
* lisp/vc/ediff-diff.el (ediff-same-contents):
* lisp/vc/vc-cvs.el (vc-cvs-mode-line-string):
* test/automated/tramp-tests.el (tramp-test33-asynchronous-requests):
Use directed rather than neutral quotes in diagnostics.

Run admin/update-copyright.

Fixes: debbugs:13689

* lisp/erc/erc-match.el (erc-match-message): Don't truncate action messages.