In particular, document 'list for-push' separately from 'list', as
the former needs only be supported for the push/export
capabilities, and the latter only for fetch/import. Indeed, a
hypothetically 'push-only' helper would only need to support the
former, not the latter.
Signed-off-by: Max Horn <max@quendi.de> Acked-by: Sverre Rabbelier <srabbelier@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>