Add checks for `Enum` and `BoundedEnum`

[garyb]

• Enum
• BoundedEnum

[jacereda]

I think I can help with these if you want.

[garyb]

That'd be great, thanks!

[jacereda]

I'll wait until purescript/purescript-enums#19 and purescript/purescript-enums#20 get merged.

[jacereda]

I've updated #23

If that one gets merged this can be closed.