[RFA/libiberty] Fix documentation issues in filename_cmp.c

[Joel Brobecker]

> I'm OK with it if Eli likes it.

Thanks! Eli was OK, so I checked this in.

> > The attached patch incorporates all the documentation changes that Eli
> > has recommended.  No code change.
> > 
> > 2007-04-05  Joel Brobecker  <brobecker@adacore.com>
> > 
> >         * filename_cmp.c (filename_cmp): Improve documentation.
> > 
> > Tested on x86-linux by rebuilding GDB. OK to apply?

-- 
Joel