Broken links in the docs

[jacklaurencegaray]

In this page:
https://www.w3.org/WAI/WCAG21/Understanding/non-text-content

Following links with these strings are broken:

• Success Criterion 4.1.2
• Guideline 1.2

[kfranqueiro]

Thanks for the report.

This is resolved now that WCAG 2.1 Techniques and Understanding Docs have been republished via the new build system, made possible by #4007.