Fix matching generic calls with AnyType when the generic argument is also a generic argument in return type, out or ref parameter

[JMolenkamp]

Allow matching the following methods with use of Arg.AnyType:

IEnumerable<T> SomeMethod<T>()
void SomeMethod<T>(out IEnumerable<T> result)
void SomeMethod<T>(ref IEnumerable<T> result)

[JMolenkamp]

Split off from #855 which contained both fixes and a feature request. This one only contains fixes.