git-config: don't silently ignore options after --list
git-config: don't silently ignore options after --list

Error out if someone gives options after --list since that is
not a valid syntax.

Signed-off-by: Frank Lichtenheld <86a8c2da8527a1c6978bdca6d7986fe14ae147fe@lichtenheld.de>
Signed-off-by: Lars Hjemli <1022a68b169538dabe33b1e3a08dffa0cefd6c22@gmail.com>
Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>

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