Improve CC Mode support for text conversion

Improve CC Mode support for text conversion

* lisp/progmodes/cc-cmds.el (c-post-text-conversion): New
function.
* lisp/progmodes/cc-mode.el (c-initialize-cc-mode): Add it as
the `post-texxt-conversion-hook'.
* lisp/simple.el (post-text-conversion-hook): New hook.
(analyze-text-conversion): Run it until success before trying
post insert functions.