Add -P to the documentation head.
Add -P to the documentation head.

This is a companion patch for 211dcac6430cdf77fcf2a968ffaf9313b5c059b0
commit, to add the newly introduced -P option to the list of options.

Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

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