bug#72442: 31.0.50; Gnus or message.el doesn't handle international message reply subject prefixes and insults users

[Eli Zaretskii <eliz@gnu.org>]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: Björn Bidar <bjorn.bidar@thaodan.de>,
>   72442@debbugs.gnu.org
> Date: Tue, 20 Aug 2024 11:46:26 +0200
> 
> >>>>> On Sat, 03 Aug 2024 20:19:48 +0300, Eli Zaretskii <eliz@gnu.org> said:
> 
>     >> From: Björn Bidar <bjorn.bidar@thaodan.de>
>     >> Cc: 72442@debbugs.gnu.org
>     >> Date: Sat, 03 Aug 2024 19:58:46 +0300
>     >> 
>     >> Eli Zaretskii <eliz@gnu.org> writes:
>     >> 
>     >> > FWIW, Rmail does support the various ways of saying "Re:", so the code
>     >> > could be lifted from there.
> 
> So does message, you just have to configure
> `message-subject-re-regexp'. The message manual contains an
> appropriate setting.

I wouldn't expect users to know how to do that in advance of getting
the various "Re:" variants out there.  Should we perhaps improve the
default value to be less English-centric?

> We could just add the example from the manual to the `defcustom' for
> `message-subject-re-regexp' (and also align it with whatever Rmail
> does).

I think good defaults here win big time.  This corner is notoriously
dark and most users will not know how to make it better.