CustomUnitAmount doesn't derive Eq, PartialEq

[appellation]

Is your feature request related to a problem? Please describe.

I've been kicking the tires on the new v1 alpha and noticed a mild annoyance that none of the 3 CustomUnitAmount structs derive Eq or PartialEq. This makes it annoying to check if they are equivalent.

Describe the solution you'd like

It should be possible to test equality between instances of CustomUnitAmount. I don't think it makes sense that they could be compared across different types, but it would make sense that we could compare the same type.

Describe alternatives you've considered

The alternative is what exists today, where it is not possible to test these structs for equality.

Additional context

No response

[mzeitlin11]

Thanks @appellation! Contributions to just add those derives in the codegen process would be welcome, we just need to make sure that the added generated code doesn't regress compile time, if so it might need a feature flag.