Update label in doc.

doc/extending/using_params.txt

@@ -76,7 +76,7 @@ attribute :attr:`params_type` to an instance of your params Type.
    If you want to have multiple parameters, Theano provides the convenient class
    :class:`theano.gof.params_type.ParamsType` that allows to bundle many parameters into
    one object that will be available in both Python (as a Python object) and C code (as a struct).
-   See :ref:`ParamsType tutorial and API documentation <libdoc_gof_wrapper>` for more infos.
+   See :ref:`ParamsType tutorial and API documentation <libdoc_gof_params_type>` for more infos.
 
 For example if we decide to use an int as the params the following
 would be appropriate:

doc/library/gof/params_type.txt

-.. _libdoc_gof_wrapper:
+.. _libdoc_gof_params_type:
 
 ============================================================
 :mod:`theano.gof.params_type` -- Wrapper class for op params