Docs: Consider relocating access tip

In PR #889, below tip was removed:

> If you access port ``4200`` via a client library or command-line tool like ``curl`` or ``wget``, the request will be handled by the `CrateDB Rest API`_, and the response will be in JSON.

Consider where that could be relevant to relocate.
Perhaps:
[Guide/Connectivity](https://cratedb.com/docs/guide/feature/connectivity/index.html#connect)
[Guide/How to connect](https://cratedb.com/docs/guide/getting-started.html#use-start-building)
[Reference/Client Interfaces](https://cratedb.com/docs/crate/reference/en/latest/interfaces/index.html)