Add representation header and replace Entity header where appropriate

[hamishwillee]

Latest HTTP spec doesn't talk about Entity headers, but "representation headers". This adds representation header docs and cross links to them from headers where appropriate. Also deprecates the entity header doc.

What was wrong/why is this fix needed? (quick summary only)

Entity headers are confusing, as we refer to them but specs do not.

I still need to update a couple of docs around General headers:

• https://developer.mozilla.org/en-US/docs/MDN/Contribute/Howto/Document_an_HTTP_header
• https://developer.mozilla.org/en-US/docs/Glossary/General_header

[github-actions]

Preview URLs

• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Glossary/HTTP_header
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Glossary/Representation_header
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Glossary/Entity_header
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Web/HTTP/Headers
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Web/HTTP/Headers/Content-Language
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Web/HTTP/Headers/Content-Type
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Web/HTTP/Headers/Content-Encoding
• https://pr4988.content.dev.mdn.mozit.cloud/en-US/docs/Web/HTTP/Headers/Content-Location

Flaws

Note! 7 documents with no flaws that don't need to be listed. 🎉

URL: /en-US/docs/Web/HTTP/Headers
Title: HTTP headers
on GitHub
Flaw count: 3

• macros:
  • /en-US/docs/Glossary/COEP does not exist
  • /en-US/docs/Glossary/COOP does not exist
  • /en-US/docs/Glossary/CORP does not exist

External URLs

URL: /en-US/docs/Glossary/HTTP_header
Title: HTTP header
on GitHub

No new external URLs

---

URL: /en-US/docs/Glossary/Representation_header
Title: Representation header
on GitHub

• https://datatracker.ietf.org/doc/html/rfc7231 (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Glossary/Entity_header
Title: Entity header
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/HTTP/Headers
Title: HTTP headers
on GitHub

• https://datatracker.ietf.org/doc/html/rfc4229 (1 time) (Note! This may be a new URL 👀)
• https://datatracker.ietf.org/doc/html/rfc6648 (1 time) (Note! This may be a new URL 👀)
• https://www.iana.org/assignments/message-headers/perm-headers.html (2 times) (Note! This may be a new URL 👀)
• https://www.iana.org/assignments/message-headers/prov-headers.html (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/HTTP/Headers/Content-Language
Title: Content-Language
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/HTTP/Headers/Content-Type
Title: Content-Type
on GitHub

No new external URLs

---

URL: /en-US/docs/Web/HTTP/Headers/Content-Encoding
Title: Content-Encoding
on GitHub

• https://en.wikipedia.org/wiki/DEFLATE (1 time) (Note! This may be a new URL 👀)
• https://tools.ietf.org/html/rfc1950 (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/HTTP/Headers/Content-Location
Title: Content-Location
on GitHub

No new external URLs

(this comment was updated 2021-05-14 07:47:32.017191)

[hamishwillee]

@Elchi3 Note, this allowed me to pull compat in using macro below. BUT I got an error pulling in specifications even though this IS defined in the compatibility info.

[Elchi3]

Thanks @hamishwillee! This will work after w3c/browser-specs#280 is fixed.

[chrisdavidmills]

LGTM; let's get this merged!