whonix_gateway/usr/share/tor/tor-service-defaults-torrc.whonix:
Let's rather link to the Whonix specific documentation https://www.whonix.org/wiki/Hidden_Services rather than https://www.torproject.org/docs/tor-hidden-service.html.en, which is Tor specific.
If we need something from https://www.torproject.org/docs/tor-hidden-service.html.en we can take it, since it's under a Free license as well.