If the user presses a key that isn't currently active then explain why
it isn't active rather than just listing all the keys. It already did
this for some keys, this patch does the same for the those that
weren't already handled.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>