bug#20702: 25.0.50; (elisp) `ImageMagick Images': say how to tell if Emacs has IM support, etc.

[Eli Zaretskii]

> Date: Sun, 31 May 2015 08:08:03 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> My guess (from trying) would be that (fboundp 'imagemagick-types) is the
> test that tells you this - in my build it returns nil.

Actually,

     M-: (image-type-available-p 'imagemagick) RET
and
     C-h v system-configuration-features RET

are better ways of getting at that information.  The latter should IMO
be documented in both manuals.