fix typo in docs

docs/src/userguide/extension_types.rst

@@ -554,9 +554,9 @@ your usage pattern.
 Controlling pickling
 ====================
 
-By default, Python will generate a ``__reduce__`` to allow pickling an extension
-type if and only if each of its members are convertible to Python and it has
-no ``__cinit__`` method.
+By default, Cython will generate a ``__reduce__()`` method to allow pickling
+an extension type if and only if each of its members are convertible to Python
+and it has no ``__cinit__`` method.
 To require this behavior (i.e. throw an error at compile time if a class
 cannot be pickled) decorate the class with ``@cython.auto_pickle(True)``.
 One can also annotate with ``@cython.auto_pickle(False)`` to get the old