grep: stop using PARSE_OPT_NO_INTERNAL_HELP
grep: stop using PARSE_OPT_NO_INTERNAL_HELP

The flag PARSE_OPT_NO_INTERNAL_HELP is set to allow overriding the
option -h, except when it's the only one given.  This is the default
behavior now, so remove the flag and the hand-rolled --help-all
handling.  The internal --help-all handler now actually shows hidden
options, i.e. --debug in this case.

Signed-off-by: Rene Scharfe <2da278a99b557fc93ddbed7517a413ad793e2e6a@web.de>
Signed-off-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>

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