Go 1.24 Generic Type Alias

[hpidcock]

Requested feature

Go 1.23 introduced generic type aliases behind a GOEXPERIMENTAL flag.
These are now available in Go 1.24. See golang/go#46477
It is desired that mockgen can generate mocks that correctly map generic type params of an
alias to the underlying generic interface type.

Why the feature is needed

When mockgen is given the name of a generic type alias that resolves
to a generic interface, with #217 fixed, it misses the mapping of generic arguments, which might be
references to generic type params from the instantiated generic alias type.

Proposed solution

TBD implements a proposed solution.