Alec Theriault authored Aug 21, 2018 and Ben Gamari committed Aug 23, 2018

Calculating which modules to load based on the InteractiveContext means
maintaining a potentially very large GblRdrEnv.

In Haddock's case, it is much cheaper (from a memory perspective) to
just keep track of which modules interfaces we want loaded then hand
these off explicitly to 'getNameToInstancesIndex'.

Bumps haddock submodule.

Reviewers: alexbiehl, bgamari

Reviewed By: alexbiehl

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D5003

(cherry picked from commit c971e119)