Support masked Var References in JSON Schema / Swagger

[ikitommi]

Extracted @bsless #985 (comment) into separate issue.

so, you would not like to expose the namespaces?

Exactly. It's an implementation detail and can just add noise and confusion. Why would the consumer care that my schema is a com.foo.my-service.blash.schema/User? The benefit is it maps directly to the place where the schema is defined. Since it has pros and cons for each option, it makes sense to make it configurable and leave it up to users.

just for Vars or also for qualified keywords and symbols?

With qualified idents you can already give them whatever namespace prefix you like (and some argue you shouldn't use a ::foo anyway), so it's less of an issue.