Improve the optional translation of quotes

Fix several problems with the recently-added custom variable
help-quote-translation where the code would quote inconsistently
in help buffers.  Add support for quoting 'like this', which
is common in other GNU programs in ASCII environments.  Change
help-quote-translation to use more mnemonic values: values are now the
initial quoting char, e.g., (setq help-quote-translation ?`) gets the
traditional Emacs help-buffer quoting style `like this'.  Change the
default behavior of substitute-command-keys to match what's done in
set-locale-environment, i.e., quote ‘like this’ if displayable,
'like this' otherwise.
* doc/lispref/help.texi (Keys in Documentation): Document
new behavior of substitute-command-keys, and document
help-quote-translation.
* doc/lispref/tips.texi (Documentation Tips):
Mention the effect of help-quote-translation.
* etc/NEWS: Mention new behavior of substitute-command-keys,
and merge help-quote-translation news into it.
When talking about doc strings, mention new ways to type quotes.
* lisp/cedet/mode-local.el (overload-docstring-extension):
Revert my recent change to this function, which shouldn't be
needed as the result is a doc string.
* lisp/cedet/mode-local.el (mode-local-print-binding)
(mode-local-describe-bindings-2):
* lisp/cedet/srecode/srt-mode.el (srecode-macro-help):
* lisp/cus-theme.el (describe-theme-1):
* lisp/descr-text.el (describe-text-properties-1, describe-char):
* lisp/emacs-lisp/cl-generic.el (cl--generic-describe):
* lisp/emacs-lisp/eieio-opt.el (eieio-help-class)
(eieio-help-constructor):
* lisp/emacs-lisp/package.el (describe-package-1):
* lisp/faces.el (describe-face):
* lisp/help-fns.el (help-fns--key-bindings)
(help-fns--compiler-macro, help-fns--parent-mode)
(help-fns--obsolete, help-fns--interactive-only)
(describe-function-1, describe-variable):
* lisp/help.el (describe-mode):
Use substitute-command-keys to ensure a more-consistent quoting
style in help buffers.
* lisp/cus-start.el (standard):
Document new help-quote-translation behavior.
* lisp/emacs-lisp/lisp-mode.el (lisp-fdefs):
* lisp/help-mode.el (help-xref-symbol-regexp, help-xref-info-regexp)
(help-xref-url-regexp):
* lisp/international/mule-cmds.el (help-xref-mule-regexp-template):
* lisp/wid-edit.el (widget-documentation-link-regexp):
Also match 'foo', in case we're in a help buffer generated when
help-quote-translation is ?'.
* src/doc.c: Include disptab.h, for DISP_CHAR_VECTOR.
(LEFT_SINGLE_QUOTATION_MARK, uLSQM0, uLSQM1, uLSQM2, uRSQM0)
(uRSQM1, uRSQM2, LSQM, RSQM): New constants.
(Fsubstitute_command_keys): Document and implement new behavior.
(Vhelp_quote_translation): Document new behavior.

1 files changed, 8 insertions, 4 deletions

diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index c8641aed8bb..a0b9ddfe2c9 100644
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -161,8 +161,11 @@ otherwise."
       ;; Buttons
       (when (and button (not (widgetp wid-button)))
 	(newline)
-	(insert "Here is a ‘" (format "%S" button-type)
-		"’ button labeled ‘" button-label "’.\n\n"))
+	(insert (substitute-command-keys "Here is a ‘")
+		(format "%S" button-type)
+		(substitute-command-keys "’ button labeled ‘")
+		button-label
+		(substitute-command-keys "’.\n\n")))
       ;; Overlays
       (when overlays
 	(newline)
@@ -738,8 +741,9 @@ relevant to POS."
                       (when face
                         (insert (propertize " " 'display '(space :align-to 5))
                                 "face: ")
-                        (insert (concat "‘" (symbol-name face) "’"))
-                        (insert "\n")))))
+                        (insert (substitute-command-keys "‘")
+                                (symbol-name face)
+                                (substitute-command-keys "’\n"))))))
               (insert "these terminal codes:\n")
               (dotimes (i (length disp-vector))
                 (insert (car (aref disp-vector i))