update-ref: mark more unused parameters in parser callbacks
This is a continuation of 44ad082968 (update-ref: mark unused parameter
in parser callbacks, 2023-08-29), as we've grown a few more virtual
functions since then.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
authored by