git p4 doc: use two-line style for options with multiple spellings
git p4 doc: use two-line style for options with multiple spellings

Thomas Rast noticed the docs have a mix of styles when
it comes to options with multiple spellings.  Standardize
the couple in git-p4.txt that are odd.

Instead of:
  -n, --dry-run::

Do this:
  -n::
  --dry-run::

See
http://thread.gmane.org/gmane.comp.version-control.git/219936/focus=219945

Signed-off-by: Pete Wyckoff <1a91d62f7ca67399625a4368a6ab5d4a3baa6073@padd.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

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