Documentation/rev-list-options.txt: fix mark-up

Some the labeled list entries have a blank line between the label
and the body text, and some don't.  Use the latter style for
consistency; incidentally, syntax highlighting in Vim works better
if there is no blank line there.

Typeset literal options, commands, and path names in monospace.
When using `literal string` mark-up to do so, there is no need to
escape AsciiDoc special characters with backslashes, so make sure we
don't do so.

Replace some double quotes with proper AsciiDoc quotes
(e.g. ``foo'').
Signed-off-by: NJason St. John <jstjohn@purdue.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>