diff: typeclass user documentation

[Fergus Henderson]

One more comment: in the TexInfo source, please make sure that
there are two spaces between each full stop and the next sentence.
Otherwise the Info version comes out inconsistent.

Once you've addressed that and my other comments, please commit it.
(Regarding the before-or-after "Modules" issue, I don't mind -- maybe
you should seek a third opinion.)

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3         |     -- the last words of T. S. Garp.