[RFA/doco] expand solib_unloaded documentation...

[Joel Brobecker]

> > 2009-09-23  Joel Brobecker  <brobecker@adacore.com>
> > 
> >         * observer.texi (solib_unloaded): Document explicitly the fact that
> >         this observer is called before the associated symbols are unloaded.
> 
> Yes, thanks.

Thanks. Checked in (HEAD only).

-- 
Joel