bug#25825: 25.1; ispell-find-hunspell-dictionaries not working on Windows

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Wed, 26 Aug 2020 13:01:21 -0700
> Cc: sw9@outlook.com, 25825@debbugs.gnu.org
> 
> > One idea to improve the situation on our end is to look for "Can't
> > open affix or dictionary files for dictionary named 'default'." and
> > raise a better error in these cases.
> 
> I think it's better to raise the more helpful error.
> 
> How does the attached diff look?

It's OK, but wouldn't it be more helpful if we added something like

  (is $LANG unset?)

to the error message text?