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

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

> I think it's okay to leave things as they are.
>
> Stefan, WDYT?

We do not want to change replace-regexp-in-string's behavior.  This
goes without saying IMO, and needs no documentation changes.

I also see nothing highly surprising or unusual about it saving match
data.  Interested users can easily read the code to see if it does,
just like Jens did.

So I also think it's fine not to change anything here, on balance.