bug#65536: 30.0.50; replace-regexp-in-string documentation does not mention it saves match data

[Eli Zaretskii]

> Date: Fri, 25 Aug 2023 15:16:29 +0200
> From:  Jens Schmidt via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Not sure about this one, maybe I have overlooked something ...
> 
> The Emacs Lisp manual says:
> 
>    Notice that all functions are allowed to overwrite the match data
>    unless they’re explicitly documented not to do so.
> 
> And in particular function `replace-regexp-in-string' could be
> assumed to modify the match data, but it uses an explicit call to
> `save-match-data' to not do so.
> 
> Maybe this should be explicitly documented in its doc string and/or
> the Emacs Lisp manual ((elisp) Search and Replace) so that users of
> the function can rely on that fact?

Is it important to promise never to clobber match-data in this
function?