WEB-2754 - format link fixes

[davidejones]

What does this PR do?

site-region can also have its own link scope. As this wasn't being accounted for it would leak into the "main" section causing the format link to say there are duplicates

Motivation

https://datadoghq.atlassian.net/browse/WEB-2754

Preview

Testing Locally i tested the following file

local/bin/py/build/actions/format_link.py -f content/en/continuous_integration/setup_pipelines/custom_tags_and_metrics.md

Trying on all files with something like

 for f in $(find ./content/en -type f -iname '*.md'); do local/bin/py/build/actions/format_link.py -f "$f"; done

However we should test multiple file changes and see how the content changes.

Additional Notes

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Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.