GHC documentation of modules exposed by the base package

[Edward Z. Yang]

The status of the documentation being hidden or exposed is due
to the {-# OPTIONS_HADDOCK hide #-}

Though, honestly, in my opinion we should still generate the
documentation in this case, just not list it in the default view.

Excerpts from Andrés Sicard-Ramírez's message of 2016-02-26 06:01:16 -0800:
> Dear all,
> 
> By running in GHC 7.10.3
> 
>   $ ghc-pkg field base-4.8.2.0 exposed-modules
> 
> I can see various modules exposed by base-4.8.2.0 which are not
> documented (e.g. GHC.NUm) in
> 
>   http://downloads.haskell.org/~ghc/7.10.3/docs/html/libraries/index.html
> 
> Which is the criterion for adding GHC documentation to the modules
> exposed by base?
> 
> All the best,
>