Summary:
`Typeable{1..7}` (type synonyms for the poly-kinded `Typeable`) have
been deprecated since GHC 7.8. They're now causing problems for users who try
to still work with them in legacy code, since they can no longer be used in
instances. To avoid this sort of confusion, let's just remove `Typeable{1..7}`
altogether. Resolves #14047.

Reviewers: bgamari, austin, hvr

Reviewed By: bgamari

Subscribers: rwbarton, thomie

GHC Trac Issues: #14047

Differential Revision: https://phabricator.haskell.org/D3817