How to document JS API objects with nested definitions

[heitortsergent]

Related to #1348.

When documenting k6's JS API, we don't currently have a great/standard way of providing a definition for the properties of objects with nested objects with them.

One way to do it is to provide multiple tables, one for each object, in the same page, although they can be a little hard to parse.

How can we improve this? How do other libraries/docs handle this?