Reinstate feature: Show ambiguous types fully qualified

[jvoigtlaender]

This feature worked on master, but got lost during the revamp.

[jvoigtlaender]

A current instance where this feature would be important: http://package.elm-lang.org/packages/elm-lang/core/3.0.0/Json-Decode#Value.

See also elm/elm-lang.org#477 (comment).

[norpan]

Since the fully qualified type is in the documentation.json this should be a simple frontend change. Even better would be to have a link to the actual type in another package, but I understand this would be more work, since that information is not available.
I'm gonna document what the Value type is in http://package.elm-lang.org/packages/norpan/elm-json-patch/1.0.0/Json-Patch but it would be great if that wasn't needed.