Consider adding a metatable field to types #12

Function entries are written to have an associated namespace rather than type. This means there's no explicit relation reflected in the yaml files between functions and the "classes" they are a "method" of.

However, the book specifically checks for Card, Effect, and Group and associates them to their respective type when generating sample code so it knows whether to recommend colon notation (c:IsCode(...) instead of Card.IsCode(c,...)).

It might be worth representing this information in the yamls rather than being hardcoded in consuming programs.