Enable derivation of `makeHFunctor` for rank-polymorphic mixed data types.

[ymdfield]

For example, the Provider effect class:

class Provider c i g (f :: Type -> Type) where
    provide :: i -> (forall h. c h => (f ~> h) -> h a) -> f (g a)

and the effect class data-type:

data ProviderH c i g f a where
    Provide :: i -> (forall h. c h => (f ~> h) -> h a) -> ProviderH c i g f (g a)

Improvement is needed to make makeHFunctor work automatically for this.