gh-96641: Do not expose KeyWrapper in _functoolsmodule.c (gh-96642)

(cherry picked from commit 2fd7246)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington

Misc/NEWS.d/next/Core and Builtins/2022-09-07-13-38-37.gh-issue-96641.wky0Fc.rst

@@ -0,0 +1 @@
+Do not expose ``KeyWrapper`` in :mod:`_functools`.

Modules/_functoolsmodule.c

@@ -1470,9 +1470,8 @@ _functools_exec(PyObject *module)
     if (state->keyobject_type == NULL) {
         return -1;
     }
-    if (PyModule_AddType(module, state->keyobject_type) < 0) {
-        return -1;
-    }
+    // keyobject_type is used only internally.
+    // So we don't expose it in module namespace.
 
     state->lru_list_elem_type = (PyTypeObject *)PyType_FromModuleAndSpec(
         module, &lru_list_elem_type_spec, NULL);