Ref T12074. This uses more consistent Conduit keys for constraint names.

This is a minor compatibility break on watchers/members but since these methods are more useful now this is probably a good time to try to get away with it, and a more consistent API is better in the long run. I need to issue compatibility guidance for the milestones thing anyway and that one isn't avoidable, so try to rip the bandage off all in one go.

Reviewed new constraint names from console, called methods using them.