Improve doc for the automated test suite

While resuming work on the test suite, I’ve stumbled upon an old branch of mine which contains fixes for the automated test suite documentation. I’ve pushed a bugfix/doc-automated-test-suite branch accordingly.

Reviews/comments welcome.

Feature Branch: bugfix/doc-automated-test-suite

Related issues

Blocks #13241 (closed)

Original created by @CyrilBrulebois on 16269 (Redmine)

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