[Discovery] add small example before we dive deep
In this section: https://github.com/cloudevents/spec/blob/541e790ef8076f889adfe7a82859f815ec80d22c/discovery.md#entities-in-the-api
I like that we give a short overview, in words, of how to view the "directory". I wonder if it would help readers if we then provided a VERY small example (even if it has lots of ... to hide some output) of what a query result would look like before we start the next section? This might help the reader mentally picture the entities and how they are related/grouped before we dive deep with the list of entities.
Even a psuedo-schema that shows the outline of the directory would be good.
Moved to https://github.com/xregistry/spec/issues/3