docs: add commonmark and gfm as versions in demo

[UziTech]

Description

Add CommonMark and GFM as version on the demo page.

CommonMark runs loads commonmark.js in the worker, and GFM calls https://api.github.com/markdown in the worker.

GFM demo

Contributor

• Test(s) exist to ensure functionality and minimize regression (if no tests added, list tests covering this PR); or,
• no tests required for this PR.
• If submitting new feature, it has been documented in the appropriate places.

Committer

In most cases, this should be a different person than the contributor.

• CI is green (no forced merge required).
• Squash and Merge PR following conventional commit guidelines.

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Project	Deployment	Actions	Updated
marked-website	Ready	Preview	Sep 13, 2026 8:26am UTC