bug#24050: 24.5; ispell-change-dictionary suggests non-existent dicts (aspell)

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: olejorgenb@gmail.com,  24050@debbugs.gnu.org
> Date: Tue, 30 Jul 2019 13:22:18 +0200
> 
> > So all of this is ... complicated.  And since the original complaint
> > is about the completion candidates shown by ispell-change-directory, I
> > think we should solve that problem by tweaking only the completion,
> > not the data structures it uses.  If you agree, maybe you or someone
> > else could come up with an alternative patch which only modified how
> > the collection of completion candidates is calculated.
> 
> A different option might be to use the current way of doing the
> completion candidates, but mark (for instance in bold) the ones that
> aspell/hunspell has said are available on the system.

Yes.  Although that would be different from the way we display
completion candidates in other cases, and might require inline
explanation.