Swagger documentation: /api/ontologies/{onto}/terms/{id} wrong or unclear

[lgatto]

Describe the bug

I am unable to execute the query /api/ontologies/{onto}/terms/{id} after trying multiple combinations of {onto} and {id}.

It is unclear whether I am doing something wrong or of there's another problem. It would be extremely useful for users to have examples - this would also have helped me deciding whether I was calling the API with the wrong parameters.

There are other API calls that I can't figure out. I believe this issue is probably related to #618.