rename test and rewrite comment

Author: AlexWaygood

src/test_typing_extensions.py

@@ -1207,9 +1207,8 @@ class My(enum.Enum):
 
         self.assertEqual(Literal[My.A].__args__, (My.A,))
 
-    def test_illegal_parameters_do_not_raise_runtime_errors(self):
-        # Type checkers should reject these types, but we do not
-        # raise errors at runtime to maintain maximum flexibility
+    def test_nested_literals_are_allowed(self):
+        # These are explicitly allowed by the typing spec
         Literal[int]
         Literal[Literal[1, 2], Literal[4, 5]]
         Literal[3j + 2, ..., ()]