Add code examples in the right column and check if json response in example is correct

[unfulvio]

REST docs are complete, however the code examples that show the reader how to make an API call have some TODOs because no code example is given, but only the JSON response.

Since this API is dependent on the WC/WP API probably we don't have to give complicated examples, and still highlight the JSON response which is more important. While at it we can check if the response example is in line with the current API iteration that Memberships ships with.

• Requested by: Chase / Fulvio