This patch modifies the renamer to respect ScopedTypeVariables in kind
signatures. This means that kind variables bound by the outermost
`forall` now scope over the type:

  type F = '[Right @a @() () :: forall a. Either a ()]
  --         ^^^^^^^^^^^^^^^          ^^^
  --          in scope here        bound here

However, any use of such variables is a type error, because we don't
have type-level lambdas to bind them in Core. This is described in the
new Note [Type variable scoping errors during type check] in GHC.Tc.Types.