[UX] limit field tokens on node type page to fields on that type

When I'm creating a path alias for a content type, I often get tripped up by the really long list of field tokens. If the list were only to contain the field tokens that would actually work for this content type, the experience of using the token browser would increase.

Additionally, we'd avoid the confusing thing that happens when you select a token that does not work for that content type, and then wonder why the pattern isn't working properly.