fix ipyparallel duplicated entry

docs/source/conf.py

@@ -225,7 +225,6 b" htmlhelp_basename = 'ipythondoc'"
 intersphinx_mapping = {'python': ('https://docs.python.org/3/', None),
                        'rpy2': ('https://rpy2.readthedocs.io/en/version_2.8.x/', None),
                        'jupyterclient': ('https://jupyter-client.readthedocs.io/en/latest/', None),
-                       'ipyparallel': ('https://ipyparallel.readthedocs.io/en/latest/', None),
                        'jupyter': ('https://jupyter.readthedocs.io/en/latest/', None),
                        'jedi': ('https://jedi.readthedocs.io/en/latest/', None),
                        'traitlets': ('https://traitlets.readthedocs.io/en/latest/', None),