doc: fix code examples in url.md

* Update outputs.
* Refine spaces.
* Restore missing part.

PR-URL: https://github.com/nodejs/node/pull/13288


Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>