bug#34594: cc-mode needs to support "final" in C++ classes

["Daniel Colascione" <dancol@dancol.org>]

> Consider this:
>
> 1 struct QueryCache final : BasePyObject, SupportsGcClear,
> 2                           HasDict, SupportsWeakRefs
>
> Without the "final", line 2 is classified as inher-cont.  With the
> "final", it gets topmost-intro-cont and wrong indentation.

Proposed fix:

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index b4c12896f3..121888d825 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -12268,6 +12268,9 @@ c-guess-basic-syntax
 			(if (eq (char-after) ?<)
 			    (zerop (c-forward-token-2 1 t indent-point))
 			  t)
+			(if (looking-at "final\\>[^_]")
+			    (c-forward-token-2 1 nil indent-point)
+			  t)
 			(eq (char-after) ?:))))
 	    (goto-char placeholder)
 	    (c-add-syntax 'inher-cont (c-point 'boi)))