bug#23179: 25.0.92; Restore `M-,' to continue etags search

[Eli Zaretskii]

> Date: Sun, 3 Apr 2016 20:49:11 +0200
> From: Anders Lindgren <andlind@gmail.com>
> Cc: Brief Busters <dgutov@yandex.ru>, 23179@debbugs.gnu.org
> 
>  > I gave the code a test. It's a step in the right direction. However, I 
> found some problems with the
>  approach
> 
>  Are these problems grave enough that you'd prefer not to use such a
>  new command?
> 
> Without a doubt, yes.
> 
> I might use some other features of xref, but I would still be using the old 
> tags-search and tags-query-replace
> commands, as the situation is right now.

What is the minimum set of changes that will cause you to change your
mind?