Export ($!) from Data.Function

[Yuras Shumovich]

Hello,

Right now ($!) operator can be imported either from Prelude or GHC.Base.
The later is specific to GHC, so it makes sense to avoid it.

There are reasons to avoid Prelude too (e.g. because it pollutes name
space, changes too often, etc.) We need a home module for all identifies
from Prelude, so that one can import them without importing Prelude.

Data.Functor seems to be a good candidate for ($!) operator home module.
It already exports ($) operator.

Thanks,
Yuras