doc: fix url example to match behavior

Fixes one WHATWG URL example to match the actual behavior.

PR-URL: https://github.com/nodejs/node/pull/23359
Fixes: https://github.com/nodejs/node/issues/22653


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>