Good Haskell Style

[Alistair Bayley]

> and the offending lines in this file are:
>
> #ifndef __HADDOCK__
>     deriving (Functor, Monad, MonadIO, MonadFix, MonadReader sess)
> #else
>     -- Haddock can't cope with the "MonadReader sess" instance
>     deriving (Functor, Monad, MonadIO, MonadFix)
> #endif
>
> so it would appear that __HADDOCK__ is not defined.

Sorry, I should have said, "so it appears that -cpp is not being used".

Alistair