tutorial: update output of git commit
tutorial: update output of git commit

Commit c85db254 changed the format of the message produced
by "git commit" when creating a commit. This patch updates
the example session in the tutorial to the new format.

It also adds in the missing diffstat summary lines, which
should have been added long ago.

Signed-off-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>
Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

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