[Feature Request]: show instantiations for records/classes as well functions in CLS

[jabraham17]

Summary of Feature

Description:
When CLS is using --resolver, it can show functions with several code lenses to see the various instantiations of a function. (See screenshot)

It would be great if we could also have this for user defined generic types from records and classes. This would allow users to inspect the genericness of their types. In the above example, record R could have methods that change behavior with different types that can be hard to see, this editor support would improve that.

Code Sample

// this is the code for the above image
record R { type t = int; }

proc foo(type t, param p = 1) param do
  return t == int && p == 2;

foo(R(real), 2);
foo(R);
foo(R(?));
foo(int, p=3);