status: respect advice.statusHints for ahead/behind advice

status: respect advice.statusHints for ahead/behind advice

If the user has unset advice.statusHints, we already
suppress the "use git reset to..." hints in each stanza. The
new "use git push to publish..." hint is the same type of
hint. Let's respect statusHints for it, rather than making
the user set yet another advice flag.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>