Summary:
Phab:D866 added the `TypeError` datatype to `Control.Exception` to represent
the error that is thrown when `-fdefer-type-errors` is on, but a changelog
entry for it was never added. In addition, it should probably be a
newtype.

Reviewers: austin, hvr, KaneTW, bgamari

Reviewed By: KaneTW, bgamari

Subscribers: thomie, KaneTW

Differential Revision: https://phabricator.haskell.org/D1873

GHC Trac Issues: #10284