t6120: fix typo in test name

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6120-describe.sh

@@ -304,7 +304,7 @@ test_expect_success 'describe chokes on severely broken submodules' '
 	mv .git/modules/sub1/ .git/modules/sub_moved &&
 	test_must_fail git describe --dirty
 '
-test_expect_success 'describe ignoring a borken submodule' '
+test_expect_success 'describe ignoring a broken submodule' '
 	git describe --broken >out &&
 	test_when_finished "mv .git/modules/sub_moved .git/modules/sub1" &&
 	grep broken out