Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Unit tests (npm test) were run locally and passed
• E2E Tests (npm run test.karma.prod) were run locally and passed
• Prettier (npm run prettier) was run locally and passed

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

there is no ADR/documentation around what flavor of markdown that is supported by https://stenciljs.com/docs/docs-readme

GitHub Issue Number: N/A

What is the new behavior?

create an adr discussing how/why the team shall adopt CommonMark as the
standard for the docs-readme output target

Does this introduce a breaking change?

• Yes
• No

Testing

I did not - mwahahahahah

Other information