Always import from sphinx.ext.autodoc.mock module instead of relying on implicit import resolution

[dionhaefner]

Summary

Fixes #159

The problem is that some extensions (like sphinx_autodoc_typehints) run this:

from sphinx.ext.autodoc.mock import mock

This causes sphinx_click to resolve its own import of mock differently, which uses:

from sphinx.ext.autodoc import mock

Before running from sphinx.ext.autodoc.mock import mock, this resolves to the mock function. After, it resolves to the mock module. This is an inherent property of the Python resolution mechanism where the module is added as an attribute of the parent module once imported.

The easiest fix to me is to side-step the issue and import from the sphinx.ext.autodoc.mock module explicitly, which is what this PR implements. This module has existed at least since Sphinx 4.0.0 (current minimum version of Sphinx) so should be backwards compatible.

Tasks

• Added unit tests
• Added documentation for new features (where applicable)
• Added release notes (using reno)
• Ran test suite and style checks and built documentation (tox)

Further details