update reference

docs/gallery/howto/autogen/parallel_wf.py

@@ -277,5 +277,4 @@ def parallel_add(nb_iterations):
 # ---------------
 # Now you learned how to run tasks in parallel you might want to know how to
 # aggregate the results of all these parallel tasks (e.g. taking the mean of
-# all computed values). For this you can further read
-# :ref:`sphx_glr_howto_autogen_aggregate.py`.
+# all computed values). For this you can further read `how to aggregate outputs <aggregate.html>`_`