Fix RST formatting and double-dash escaping in config

[OlenaYefymenko]

This patch applies RST formatting to the configuration document, in particular it:

• Adds the :file: role for .coveragerc, setup.cfg, pyproject.toml, and tox.ini;
• Fixes the CLI options list formatting by switching to .. option:: directives;
• Removes a stray > from the addopts reference URL;
• Uses double backticks for --cov= and --cov-report= to prevent RST from rendering - as an em dash.

[OlenaYefymenko]

This is how it was rendered before the fix:

[webknjaz]

This doesn't seem to be enough. And also, the unquoted options are seen in multiple places in that paragraph.

[OlenaYefymenko]

This doesn't seem to be enough. And also, the unquoted options are seen in multiple places in that paragraph.

Thank you for the review!

[OlenaYefymenko]

Checked HTML rendering locally via sphinx-build

[webknjaz]

@ionelmc FTR, the linkcheck issues are related to GitHub's recent increase in aggressive rate limiting measures of unauthenticated HTTP requests.

[ionelmc]

That is fine. There's no release automation depending on that completing. Thanks everyone.