"log --cherry-pick" documentation regression fix

"log --cherry-pick" documentation regression fix

Earlier f98fd43 (git-log.txt,rev-list-options.txt: put option blocks in
proper order, 2011-03-08) moved the text around in the documentation for
options in the rev-list family of commands such as "log".  Consequently,
the description of the --cherry-pick option appears way above the
description of the --left-right option now.

But the description of the --cherry-pick option still refers to the
example for the --left-right option, like this:

    ... with --left-right, like the example ABOVE in the description of
    that option.

Rephrase it to clarify that we are making a forward reference.

Signed-off-by: Junio C Hamano <gitster@pobox.com>