fix(http): Fix headers doc to consider major protocol versions

[bsmth]

Description

The HTTP headers page can be more consistent across major protocol versions. This is a small PR to tidy up the language, seeing as more detailed improvements went into the messages page recently.

Related issues and pull requests

Fixes #20744

[github-actions]

Preview URLs

• /en-US/docs/Web/HTTP/Headers

External URLs (4)

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

• 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://github.com/protocol-registries/http-fields?tab=readme-ov-file (1 time) (Note! This may be a new URL 👀)
• https://www.iana.org/assignments/http-fields/http-fields.xhtml (2 times) (Note! This may be a new URL 👀)

(comment last updated: 2024-12-13 08:57:24)

[hamishwillee]

@bsmth A couple of comments for you to review. Approving so you are not blocked.

[bsmth]

Thanks a lot Hamish 👍🏻