Eta-reduce type-synonyms

[phadej]

Now (soon)

type Lens s t a b = Optic A_Lens '[] s t a b

Or should we have just

type Lens = Optic A_Lens '[]

[kosmikus]

Isn't the problem that this breaks down for e.g. Lens'? We have Optic', but that's also a type synonym and therefore cannot be partially applied.

So for overall symmetry, I think it might be best to keep everything eta-expanded in this case.

[phadej]

@kosmikus fair point.