Update sphinx to 3.1.2

[pyup-bot]

This PR updates sphinx from 3.1.1 to 3.1.2.

Changelog

3.1.2

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

Incompatible changes
--------------------

* 7650: autodoc: the signature of base function will be shown for decorated
functions, not a signature of decorator

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

* 7844: autodoc: Failed to detect module when relative module name given
* 7856: autodoc: AttributeError is raised when non-class object is given to
the autoclass directive
* 7850: autodoc: KeyError is raised for invalid mark up when autodoc_typehints
is 'description'
* 7812: autodoc: crashed if the target name matches to both an attribute and
module that are same name
* 7650: autodoc: function signature becomes ``(*args, **kwargs)`` if the
function is decorated by generic decorator
* 7812: autosummary: generates broken stub files if the target code contains
an attribute and module that are same name
* 7806: viewcode: Failed to resolve viewcode references on 3rd party builders
* 7838: html theme: List items have extra vertical space
* 7878: html theme: Undesired interaction between "overflow" and "float"

Links

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