test: Write test for bad pattern: .md/#

[PeterNitsche]

Changes

• I have added a test checking for invalid links to other markdown files in the markdown documentation.
• I have generalize the test file for website documentation tests to support all kind of documentations and improved the structuring of the test file.
• I have removed the test case for relatedOptions. The test case is not related to documentation and is also never executed since relatedOptions is always empty. Since relatedOptions was only referenced in the removed test and has no further meaning, I have removed it from the typings as well.

Context

Closes #23329

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[PeterNitsche]

@viceice Could you approve the workflow runs please?

[viceice]

please don't update branch if not necessary, we will use merge queue which squashes all commits

[HonkingGoose]

@PeterNitsche Congratulations on getting your first Renovate contribution merged! 🥳✨

[renovate-release]

🎉 This PR is included in version 36.26.0 🎉

The release is available on:

• GitHub release
• 36.26.0

Your semantic-release bot 📦🚀