Render Markdown if we get an Accept text/markdown header

[WalshyDev]

Summary

If an incoming request says they accept Markdown, render that instead of the usual HTML page. This can help reduce token usage for LLMs.

Test with:

$ curl https://walshy-accept-markdown.preview.developers.cloudflare.com/workers/static-assets/binding/ -H 'Accept: text/markdown' -v

Documentation checklist

• Is there a changelog entry (guidelines)? If you don't add one for something awesome and new (however small) — how will our customers find out? Changelogs are automatically posted to RSS feeds, the Discord, and X.
• The documentation style guide has been adhered to.
• If a larger change - such as adding a new page- an issue has been opened in relation to any incorrect or out of date information that this PR fixes.
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[github-actions]

Preview URL: https://024d58b6.preview.developers.cloudflare.com
Preview Branch URL: https://walshy-accept-markdown.preview.developers.cloudflare.com

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
*.ts	@cloudflare/developer-advocacy, @kristianfreeman, @kodster28, @pedrosousa, @haleycode, @GregBrimble, @KianNH, @WalshyDev

[erify-world]

This pull request updates both the middleware and worker logic to better handle requests for Markdown content. Now, requests with an Accept header indicating a preference for Markdown (text/markdown) will be treated the same as requests directly for /index.md files. This ensures that clients explicitly requesting Markdown receive the appropriate content, improving content negotiation and client compatibility.

Content negotiation improvements:

• Updated the condition in src/middleware/index.ts to serve Markdown content not only for paths ending with /index.md, but also when the Accept header includes text/markdown.
• Made a corresponding update in worker/index.ts to apply the same logic, ensuring consistent behavior between the middleware and worker entrypoint.

[erify-world]

💎🔥 Nice improvement!

This PR enhances the markdown routing logic so requests with an Accept: text/markdown header are now correctly served with the markdown content, not only /index.md paths.

Key points checked:
• ✅ Middleware (src/middleware/index.ts) updated to handle text/markdown.
• ✅ Worker entrypoint (worker/index.ts) aligned with the same logic for consistency.
• ✅ Ensures better support for clients that explicitly request markdown.

Looks solid — this should improve developer experience and interoperability when consuming docs via APIs. 🚀