[chore] [editorial] Switch registry docs to pre-processed frontmatter

[thompson-tomo]

Progresses #1821

Changes

This switches the registry docs to use frontmatter syntax rather than embedding the frontmatter in comments. Currently these comments need to be processed before they can be used on the website version.

This change will also help in reviews as the link title etc are front and center.

The docs now have an explicit title front matter property which matches h1.

No manual changes made other than to the jinja template.

Important

Pull requests acceptance are subject to the triage process as described in Issue and PR Triage Management.
PRs that do not follow the guidance above, may be automatically rejected and closed.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• Links to the prototypes or existing instrumentations (when adding or changing conventions)

[github-actions]

This PR has been labeled as stale due to lack of activity. It will be automatically closed if there is no further activity over the next 7 days.

[github-actions]

This PR has been labeled as stale due to lack of activity. It will be automatically closed if there is no further activity over the next 7 days.

[github-actions]

This PR has been labeled as stale due to lack of activity. It will be automatically closed if there is no further activity over the next 7 days.

[thompson-tomo]

@chalin could you confirm the key thing needed for #1821 is setting of the title as a front matter property like done here by updating the title? Thanks

[github-actions]

This PR has been labeled as stale due to lack of activity. It will be automatically closed if there is no further activity over the next 7 days.

[chalin]

Not stale.

[joaopgrassi]

@chalin I guess "code owner" here would be you. Can you approve to make sure from the OTel website things look ok?