Display qualifiers for both types in an error message when they share the same name

[lpil]

Currently we qualify the second type when there is a name clash:

#(Message, app/queue.Message)

This helps a lot, but sometimes it is unclear where the first type is defined. Qualify them both to resolve this problem.

#(app/actor.Message, app/queue.Message)

To do this we will need to traverse all the types once before printing any of them to identify names that are used multiple times.