bug#9591: 24.0.50; buffer name completion

[Eli Zaretskii]

> From: Stephen Berman <stephen.berman@gmx.net>
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>,  rms@gnu.org,  
> 9591@debbugs.gnu.org
> Date: Mon, 26 Sep 2011 09:56:12 +0200
> 
> > But `substring' is not in the default value of completion-styles.  So
> > how does it come into play here?
> 
> Via completion-category-overrides; with emacs -Q:

Thanks.  This variable should be mentioned in the doc string of
completion-styles, IMO.

Armed with this new knowledge, I customized
completion-category-overrides to nil and completion-styles to
`(emacs22), and the result is the kind of completion that Richard
wanted and expected.