Fix documentation for testing skipping the deletion of 3PID invite tokens

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

tests/test_invites.py

@@ -67,8 +67,7 @@ class ThreepidInvitesTestCase(unittest.TestCase):
 
 
 class ThreepidInvitesNoDeleteTestCase(unittest.TestCase):
-    """Tests that a Sydent configured to not delete 3PID invite tokens on bind skips that
-    deletion step
+    """Test that invite tokens are not deleted when that is disabled.
     """
 
     def setUp(self):