Fun idea: Units

[ivanperez-keera]

Someone in a meeting today asked me if Copilot could handle types with different units, and they also asked about the runtime cost.

It'd be a fun thing to play with, if anybody feels inclined.

I think if we can leverage dependent types, we can achieve it without any runtime cost.

We'd need to unlock #58 or relax the constraints on the type Type from https://hackage.haskell.org/package/copilot-core-4.2/docs/Copilot-Core-Type.html.