public-inbox.org links include the whole message ID by default. This
means the message can still be found even if the site goes away, which
is not the case with the marc.info link. Replace the marc.info link
with a more future proof one.
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>