Add Outputable instance for Node
Add Outputable instance for Node

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3564

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