Bug#682347: mark 'editor' virtual package name as obsolete

[Christoph Berg <myon@debian.org>]

Re: Russ Allbery 2017-12-26 <[🔎] 87wp1as3na.fsf@hope.eyrie.org>
> 1. Status quo: there is an undocumented editor virtual package, Policy
>    says that nothing has to provide or depend on it, and some random
>    collection of editors provide it.  I think this is a bad place to be,
>    so I would hope we can rule out sticking with that status quo.

I agree that the status quo is suboptimal. My concern is merely that
we shouldn't end up tearing a half-working system down just because (?)
properly fixing it is more work than tearing it down.

Provided that I'm not going to be the one doing the work, I won't
object to whatever solution is picked. Please go ahead!

Merry Christmas,
Christoph