bug#65347: 29.1; Underscore in query replace prevents case-matching

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Eli Zaretskii <eliz@gnu.org>,  65347@debbugs.gnu.org
> Date: Thu, 17 Aug 2023 22:04:53 -0400
> 
> > Although, a further relevant question: is there some way to make _ not
> > be a word separator, in this specific context?  Without changing the
> > syntax table of the buffer overall?  So that foo_bar is interpreted as
> > one word?
> 
> There's `superword-mode`, but I suspect that query-replace does not
> honor it in this case.  Could be considered as a bug in
> `superword-mode`.

Actually, I think it's a bug in replace-match: it doesn't honor
find-word-boundary-function-table.  I think it should.  Patches
welcome.