Changes to ghc

Changes to ghc:
commit ede5b5180c2a5db3f51b01dbef402d21ace9601c
Author: Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Date:   Tue Feb 25 06:35:10 2014 +0000

    Make Outputable instance for HsDocString useful

    Seeing "<document comment>" when trying to debug things in Haddock is
    utterly useless and because this instance exists, we can't even make our
    own. No instance at all would be better than what it was!

    Admittedly, this doesn't produce the nicest output. Perhaps wrapping the
    comments in {- -} would be in order but I think it's fine until someone
    complains.