Extend ‘format’ to translate curved quotes

This is a followup to the recent doc string change, and deals with
diagnostics and the like.  This patch is more conservative than
the doc string change, in that the behavior of ‘format’ changes
only if its first arg contains curved quotes and the user prefers
straight or grave quotes.  (Come to think of it, perhaps we should
be similarly conservative with doc strings too, but that can wait.)
The upside of this conservatism is that existing usage is almost
surely unaffected.  The downside is that we'll eventually have to
change Emacs's format strings to use curved quotes in places where
the user might want curved quotes, but that's a simple and
mechanical translation that I'm willing to do later.  (Bug#21222)
* doc/lispref/help.texi (Keys in Documentation):
Move description of text-quoting-style from here ...
* doc/lispref/strings.texi (Formatting Strings):
... to here, and describe new behavior of ‘format’.
* etc/NEWS: Describe new behavior.
* lisp/calc/calc-help.el (calc-describe-thing):
* lisp/emacs-lisp/derived.el (derived-mode-make-docstring):
* lisp/info.el (Info-find-index-name):
Use ‘concat’ rather than ‘format’ to avoid misinterpretation
of recently-added curved quotes.
* src/doc.c (uLSQM0, uLSQM1, uLSQM2, uRSQM0, uRSQM1, uRSQM2):
Move from here ...
* src/lisp.h: ... to here.
* src/doc.c (text_quoting_style): New function.
(Fsubstitute_command_keys): Use it.
* src/editfns.c (Fformat): Implement new behavior.
* src/lisp.h (enum text_quoting_style): New enum.

3 files changed, 8 insertions, 5 deletions

diff --git a/lisp/calc/calc-help.el b/lisp/calc/calc-help.el
index b2e7df1b718..7a1a983e6b3 100644
--- a/lisp/calc/calc-help.el
+++ b/lisp/calc/calc-help.el
@@ -365,7 +365,7 @@ C-w  Describe how there is no warranty for Calc."
     (let (Info-history)
       (Info-goto-node (buffer-substring (match-beginning 1) (match-end 1))))
     (let* ((string-target (or target thing))
-           (quoted (format "['`‘]%s['’]" (regexp-quote string-target)))
+           (quoted (concat "['`‘]" (regexp-quote string-target) "['’]"))
            (bracketed (format "\\[%s\\]\\|(%s)\\|\\<The[ \n]%s"
                               quoted quoted quoted)))
       (or (let ((case-fold-search nil))
diff --git a/lisp/emacs-lisp/derived.el b/lisp/emacs-lisp/derived.el
index ee137f1771e..1f8572b278b 100644
--- a/lisp/emacs-lisp/derived.el
+++ b/lisp/emacs-lisp/derived.el
@@ -331,9 +331,10 @@ which more-or-less shadow%s %s's corresponding table%s."
 			"\n\nThis mode "
 		      (concat
 		       "\n\nIn addition to any hooks its parent mode "
-		       (if (string-match (format "[`‘]%s['’]"
+		       (if (string-match (concat "[`%‘]"
                                                  (regexp-quote
-						  (symbol-name parent)))
+						  (symbol-name parent))
+                                                 "['%’]")
 					 docstring)
                            nil
 			 (format "`%s' " parent))
diff --git a/lisp/info.el b/lisp/info.el
index 0a2206d61bf..1b02c3585b1 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -3398,10 +3398,12 @@ Give an empty topic name to go to the Index node itself."
 	    (re-search-forward (format
                                 "[a-zA-Z]+: [a-zA-Z0-9_ *&]+ %s\\( \\|$\\)"
                                 (regexp-quote name)) nil t)
-	    (search-forward (format "['`‘]%s['’]" name) nil t)
+	    (search-forward (concat "['`‘]" name "['’]") nil t)
 	    (and (string-match "\\`.*\\( (.*)\\)\\'" name)
 		 (search-forward
-		  (format "['`‘]%s['’]" (substring name 0 (match-beginning 1)))
+		  (concat "['`%‘]"
+                          (substring name 0 (match-beginning 1))
+                          "['%’]")
 		  nil t))
 	    (search-forward name nil t)
 	    ;; Try again without the " <1>" makeinfo can append