doc: update code examples for `node:url` module

There are many things called `url` in this page including `url` module,
`URL` instances, etc.

The original example was not clear where these methods come from.

PR-URL: https://github.com/nodejs/node/pull/38645


Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>