document 'quiet' receive-pack capability
document 'quiet' receive-pack capability

This was added in c207e34 (fix push --quiet: add 'quiet'
capability to receive-pack, 2012-01-08) but never
documented.

Signed-off-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git