Add rule requiring type parameters

[marekdedic]

Hi,
I'd like to add a rule that requires type parameters to vi.fn() because otherwise it mocks a function with any as parameters and return value. I am at the moment not sure if there are any other functions that this rule should apply to similarly.

I'm willing to make a PR if this is greenlit by the maintainers.

[veritem]

hey @marekdedic, a pr is welcome! let's start with vi.fn() for now