diff: allow unstuck arguments with --diff-algorithm
diff: allow unstuck arguments with --diff-algorithm

The argument to --diff-algorithm is mandatory, so there is no reason to
require the argument to be stuck to the option with '='.  Change this
for consistency with other Git commands.

Note that this does not change the handling of diff-algorithm in
merge-recursive.c since the primary interface to that is via the -X
option to 'git merge' where the unstuck form does not make sense.

Signed-off-by: John Keeping <a51dda7c7ff50b61eaea0444371f4a6a9301e501@keeping.me.uk>
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