resolver: Disambiguate generic args

resolver: Disambiguate generic args

This removes all the hacks previously introduced to resolve ambiguous
generic args as types, and adds proper disambiguation.

The algorithm is as follows:

is that name referring to a type?
-> disambiguate to a type
is that name referring to a value?
-> disambiguate to a const value
else
-> disambiguate to type

Since types are the default expected behavior, this allows us to report
type errors properly during typechecking.