CC Mode: Correct some regexp typos, \\(:? -> \\(?:

This partly corrects bug#64069.

* lisp/progmodes/cc-langs.el (c-ml-string-back-closer-re): Fix
four occurrences, one of which was in a comment, one in a doc
string.

* lisp/progmodes/cc-mode.el (c-or-c++-mode--regexp.): Fix one
occurrence.

2 files changed, 4 insertions, 4 deletions

diff --git a/lisp/progmodes/cc-langs.el b/lisp/progmodes/cc-langs.el
index 3b4fdc6e141..ffb8c5c7b16 100644
--- a/lisp/progmodes/cc-langs.el
+++ b/lisp/progmodes/cc-langs.el
@@ -739,11 +739,11 @@ When non-nil, this variable should end in \"\\\\\\==\".  Note that
 such a backward search will match a minimal string, so a
 \"context character\" is probably needed at the start of the
 regexp.  The value for csharp-mode would be something like
-\"\\\\(:?\\\\`\\\\|[^\\\"]\\\\)\\\"*\\\\\\==\"."
+\"\\\\(?:\\\\`\\\\|[^\\\"]\\\\)\\\"*\\\\\\==\"."
   t nil
-  pike "\\(:?\\`\\|[^\\\"]\\)\\(:?\\\\.\\)*\\="
+  pike "\\(?:\\`\\|[^\\\"]\\)\\(?:\\\\.\\)*\\="
   ;;pike ;; 2
-  ;;    "\\(:?\\`\\|[^\"]\\)\"*\\="
+  ;;    "\\(?:\\`\\|[^\"]\\)\"*\\="
   )
 (c-lang-defvar c-ml-string-back-closer-re
                (c-lang-const c-ml-string-back-closer-re))
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 11a1d3fe6c2..5cf9b7e17f8 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -2859,7 +2859,7 @@ Key bindings:
                                      "\\|" id "::"
                                      "\\|" id ws-maybe "=\\)"
               "\\|" "\\(?:inline" ws "\\)?namespace"
-                    "\\(:?" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
+                    "\\(?:" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
               "\\|" "class"     ws id
                     "\\(?:" ws "final" "\\)?" ws-maybe "[:{;\n]"
               "\\|" "struct"     ws id "\\(?:" ws "final" ws-maybe "[:{\n]"