thomasw authored Jul 20, 2016 and Ben Gamari committed Jul 20, 2016

* Update the sample error messages. The messages have been reworded and
  reformatted since GHC 7.10.

* Mention `TypeApplications` in "Where can they occur?"

* The name of a named wild card is no longer used in the name of a
  resulting type variable. Before: `_foo` => `w_foo`, now: `_foo` => `t`
  or `a`.

Test Plan: generate the users guide

Reviewers: goldfire, austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2413

GHC Trac Issues: #12365