Docs: inlcude formatter documentation on website

[retrohacker]

Note: Once this PR lands, we need to open a PR against the website updating the docs.yml file, updating the gitsha for this project, and trigger a rebuild of the website.

Pre-Submission Checklist

• Opened an issue discussing these changes before opening the PR
• Ran the linter and tests via make prepush
• Included comprehensive and convincing tests for changes

Issues

Closes: #1594

We had a breaking change to the formatter API (we dropped support for async formatters) but the website was missing documentation so this wasn't apparent to the community.

Changes

• Generate documentation for the formatter files
• Add a type definition for the formatter function API

Broken windows

Fixing a few things I noticed.

• Re-running docs updated the MDN links (sorry for the large commit)
• server was misspelled as srv in a few places