Comment 0 for bug 1772104

As noted in https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1741928
and https://bugzilla.gnome.org/show_bug.cgi?id=788714

The Automatic time zone feature doesn't work when Location Services is disabled in the Privacy settings of Gnome.

This should be noted in the help documentation at
https://help.ubuntu.com/stable/ubuntu-help/clock-timezone.html