Documentation/git-format-patch.txt: Add --signoff, --check, and long option-names.
The documentation was lacking descriptions for the --signoff and --check
options to git-format-patch. It was also missing the following long
option-names: --output-directory (-o), --numbered (-n), --keep-subject
(-k), --author (-a), --date (-d), and --mbox (-m).
Signed-off-by: Nikolai Weibull <nikolai@bitwi.se> Signed-off-by: Junio C Hamano <junkio@cox.net>