Update sphinx to 1.7.3

[pyup-bot]

This PR updates Sphinx from 1.7.2 to 1.7.3.

Changelog

1.7.3

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

Bugs fixed
----------

* 4769: autodoc loses the first staticmethod parameter
* 4790: autosummary: too wide two column tables in PDF builds
* 4795: Latex customization via ``_templates/longtable.tex_t`` is broken
* 4789: imgconverter: confused by convert.exe of Windows
* 4783: On windows, Sphinx crashed when drives of srcdir and outdir are
different
* 4812: autodoc ignores type annotated variables
* 4817: wrong URLs on warning messages
* 4784: latex: :confval:`latex_show_urls` assigns incorrect footnote numbers if
hyperlinks exists inside substitutions
* 4837: latex with class memoir Error: Font command ``\sf`` is not supported
* 4803: latex: too slow in proportion to number of auto numbered footnotes
* 4838: htmlhelp: The entries in .hhp file is not ordered
* toctree directive tries to glob for URL having query_string
* 4871: html search: Upper characters problem in German
* 4717: latex: Compilation for German docs failed with LuaLaTeX and XeLaTeX
* 4459: duplicated labels detector does not work well in parallel build
* 4878: Crashed with extension which returns invalid metadata

Links

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

[coveralls]

Coverage remained the same at 93.182% when pulling a4df442 on pyup-update-sphinx-1.7.2-to-1.7.3 into 9f97d0f on master.