bug#25428: 25.1; Incorrect doc string for `delete-selection-mode'

[Eli Zaretskii]

> Date: Wed, 16 Aug 2017 20:25:31 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 25428@debbugs.gnu.org
> 
> Let's just say that the doc string is incomplete and can easily
> mislead.
> 
> If it says anything about interactive behavior (and it should)
> then it should say just what the description of `define-minor-mode'
> says for minor modes.
> 
> If it says anything about the behavior when called from
> Lisp (and it should) then it should say just what the d-m-m
> description says. This (i.e., _all_ of the d-m-m description)
> is missing from the d-s-m doc string:
> 
> * `toggle' toggles
> * non-positive integer disables
> * anything else enables

Thanks, I fixed the doc string to include the missing information.