bpo-34762: Fix contextvars C API to use PyObject* pointer types. (GH-9473)

(cherry picked from commit 2ec872b31e25cee1f983fe07991fb53f3fd1cbac)

Co-authored-by: Yury Selivanov <yury@magic.io>
diff --git a/Modules/_contextvarsmodule.c b/Modules/_contextvarsmodule.c
index b7d112d..71dd7fd 100644
--- a/Modules/_contextvarsmodule.c
+++ b/Modules/_contextvarsmodule.c
@@ -16,7 +16,7 @@
 _contextvars_copy_context_impl(PyObject *module)
 /*[clinic end generated code: output=1fcd5da7225c4fa9 input=89bb9ae485888440]*/
 {
-    return (PyObject *)PyContext_CopyCurrent();
+    return PyContext_CopyCurrent();
 }