doc: http.request and https.request accepts WHATWG URL object as argument

[joyeecheung]

• Version: master
• Subsystem: doc

After #10638 http.request and https.request (hence http.get and https.get) takes an WHATWG URL object as argument. This has not been documented yet and can be a good first contribution. Changing the type annotations in doc/api/http.md and doc/api/https.md and the description of those arguments should be enough.