t2402: fix typo

In c57b3367be (worktree: teach `list` to annotate locked worktree,
2020-10-11), we introduced a test case that wanted to talk about
"worktrees" but talked about "worktress" instead. Let's fix that.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t2402-worktree-list.sh

@@ -61,7 +61,7 @@ test_expect_success '"list" all worktrees --porcelain' '
 	test_cmp expect actual
 '
 
-test_expect_success '"list" all worktress with locked annotation' '
+test_expect_success '"list" all worktrees with locked annotation' '
 	test_when_finished "rm -rf locked unlocked out && git worktree prune" &&
 	git worktree add --detach locked master &&
 	git worktree add --detach unlocked master &&