fixup! Test without warning suppression

Author: HexDecimal

src/test_typing_extensions.py

@@ -9595,9 +9595,6 @@ def test_sentinel_picklable_anonymous(self):
                 self.assertIs(anonymous_sentinel, pickle.loads(pickle.dumps(anonymous_sentinel, protocol=proto)))
 
     def test_sentinel_deprecated(self):
-        with self.assertWarnsRegex(DeprecationWarning, r"Subclassing sentinel is forbidden by PEP 661"):
-            class SentinelSubclass(Sentinel):
-                pass
 
         with self.assertWarnsRegex(DeprecationWarning, r"Sentinel was renamed to typing_extensions.sentinel"):
             my_sentinel = Sentinel(name="my_sentinel")

src/typing_extensions.py

@@ -448,9 +448,11 @@ def __reduce__(self) -> str:
         """Reduce this sentinel to a singleton."""
         return self.__name__  # Module is taken from the __module__ attribute
 
-@deprecated("""Sentinel was renamed to typing_extensions.sentinel""")
-class Sentinel(sentinel):
-    pass
+with warnings.catch_warnings():  # Allow sentinel subclass for backwards compatibility
+    warnings.simplefilter("ignore")
+
+    class Sentinel(sentinel):
+        pass
 
 _marker = sentinel("sentinel")