docs: make markdown compatible with mdx v3

[reubenmiller]

Proposed changes

• Prepare markdown docs to be compatible with MDX v3 to enable an upgrade of the doc engine (docusaurus, from v2 to v3).
• Include PR check task to validate the docs to avoid publishing invalid markdown docs which will prevent the docs from being published
• Fix broken anchors (as docusaurus v3 can validate broken anchors in addition to broken links)

Notes

The docusaurus website has details about differences and how to upgrade

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
380	0	3	380	100	52m55.958s

[didier-wenzek]

Approved.

This is working fine in combination with thin-edge/tedge-docs#55 updating to docusaurus v3
as well as without these updates.