Big diff: Use new "|" union syntax (#5872)

stdlib/copyreg.pyi

@@ -7,8 +7,8 @@ __all__: List[str]
 
 def pickle(
     ob_type: _TypeT,
-    pickle_function: Callable[[_TypeT], Union[str, _Reduce[_TypeT]]],
-    constructor_ob: Optional[Callable[[_Reduce[_TypeT]], _TypeT]] = ...,
+    pickle_function: Callable[[_TypeT], str | _Reduce[_TypeT]],
+    constructor_ob: Callable[[_Reduce[_TypeT]], _TypeT] | None = ...,
 ) -> None: ...
 def constructor(object: Callable[[_Reduce[_TypeT]], _TypeT]) -> None: ...
 def add_extension(module: Hashable, name: Hashable, code: SupportsInt) -> None: ...