move Cardinality to type level

[matthewleon]

Once purescript/purescript#3058 is merged, perhaps BoundedEnum could get a new param, with its cardinality defined at type level, with a fundep from the type to the cardinality.

[garyb]

Does that give us any advantages? It also kinda clutters up the constraint, since we don't have associated types.

[matthewleon]

Honestly this might be excessive zeal for safety on my part. My thinking was that it allows this Range idea that I'm working on to have a type-level natural as well, which would mean that you could get an efficient toEnum' that lacks a Maybe, if you were to use the types from modular-arithmetic. But really, that is probably getting to the point of being cumbersome. And it could be defined in a separate lib, too.

If I can't think of something better here, I could close this.

[matthewleon]

I think I can accomplish what I'm looking for without this.