Quick Assists for Class Modifiers

[pq]

No description provided.

[keertip]

Some assists to be looked at:

• convert class to enum
• convert class to mixin

[bwilkerson]

Would either of these require either (a) validating that the class isn't being used outside the defining library in a way that would prohibit the change or (b) making changes outside the defining library in order to account for the change?

[keertip]

These are quick assists that exist today. Added tests to the assists to make sure they don't trigger in invalid cases and work in other cases.