Update sphinx to 1.8.5

[pyup-bot]

This PR updates Sphinx from 1.8.4 to 1.8.5.

Changelog

1.8.5

==============================

Dependencies
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Incompatible changes
--------------------

Deprecated
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Features added
--------------

Bugs fixed
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* LaTeX: Remove extraneous space after author names on PDF title page (refs: 6004)
* 6026: LaTeX: A cross reference to definition list does not work
* 6046: LaTeX: ``TypeError`` is raised when invalid latex_elements given
* 6067: LaTeX: images having a target are concatenated to next line
* 6067: LaTeX: images having a target are not aligned even if specified
* 6019: imgconverter: Including multipage PDF fails
* 6047: autodoc: ``autofunction`` emits a warning for method objects
* 6028: graphviz: Ensure the graphviz filenames are reproducible
* 6068: doctest: ``skipif`` option may remove the code block from documentation
* 6136: ``:name:`` option for ``math`` directive causes a crash
* 6139: intersphinx: ValueError on failure reporting
* 6135: changes: Fix UnboundLocalError when any module found

Testing
--------

Links

• PyPI: https://pypi.org/project/sphinx
• Changelog: https://pyup.io/changelogs/sphinx/
• Homepage: http://sphinx-doc.org/

[pyup-bot]

Closing this in favor of #12