Elaborate further on ZipList Applicative docs
Elaborate further on ZipList Applicative docs

I was initially confused when I read "zipWithn" in the haddock for 
ZipList, went looking for a function named "zipWithn", and found that 
it didn't exist. This expands the docs to clarify that we're referring 
to the family of functions [zipWith, zipWith3, zipWith4, ...], 
capitalizes the letter "n" in "zipWithN" in attempt to make that more 
readable, and gives an example.

I also moved this documentation from ZipList itself to the Applicative 
instance, so that it will show up in both the Ziplist documentation and 
in the list of Applicative instances.

Reviewers: austin, hvr, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3324

shlevy/ghc,ezyang/ghc,ezyang/ghc,shlevy/ghc,sdiehl/ghc,ezyang/ghc,shlevy/ghc,ezyang/ghc,sdiehl/ghc,sdiehl/ghc,ezyang/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,ezyang/ghc,shlevy/ghc,sdiehl/ghc,shlevy/ghc,shlevy/ghc,sdiehl/ghc,ezyang/ghc