gh-131117: Update tp_finalize example to use PyErr_GetRaisedException (#131118)

The tp_finalize C API doc used PyErr_Fetch() and PyErr_Restore() in
its example code. That API was deprecated in 3.12.

Update to point to the suggested replacement function
PyErr_GetRaisedException() which has a sample usage.

Author: cmaloney

Doc/c-api/typeobj.rst

@@ -2154,15 +2154,13 @@ and :c:data:`PyType_Type` effectively act as defaults.)
       static void
       local_finalize(PyObject *self)
       {
-          PyObject *error_type, *error_value, *error_traceback;
-
           /* Save the current exception, if any. */
-          PyErr_Fetch(&error_type, &error_value, &error_traceback);
+          PyObject *exc = PyErr_GetRaisedException();
 
           /* ... */
 
           /* Restore the saved exception. */
-          PyErr_Restore(error_type, error_value, error_traceback);
+          PyErr_SetRaisedException(exc);
       }
 
    **Inheritance:**