Test suite compatibility with docutils 0.22

[amotl]

Describe the bug

context
When I run the test suite with docutils 0.22.

expectation
I expected it to succeed.

bug
But instead it failed, until all the snippets will be adjusted for boolean value renderings like @LocutusOfBorg is exercising.

problem
This is a problem for people aiming to support multiple versions of docutils because you can't predict which library version is accompanied by Sphinx.

references

• Fix build failure with newer sphinx dependencies: #244
• Add compatibility with docutils 0.22 tech-writing/sphinx-design-elements#166 (review)

Reproduce the bug

We've only reproduced it on the downstream sphinx-design-elements project, but @LocutusOfBorg also reproduced it on sphinx-design.

List your environment

Plain Sphinx, any version, but docutils (0.19, 0.20, 0.21) vs. 0.22. 💥

Workaround

We added a workaround (see below) to the test suite of sphinx-design-elements per patch_snippet_docutils_{forward,reverse} to accompany the test suite without needing to change the snippets themselves, in order to be able to support multiple versions of docutils. However, the workaround feels dirty. Maybe you can come up with a better solution?

[chrisjsewell]

Currently blocked on Currently blocked on #248