Remove obsolete CSP referrer directive

[Elchi3]

BCD PR: mdn/browser-compat-data#23776

Redirect to https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy

[bsmth]

LGTM, thank you!

[github-actions]

Preview URLs

• /en-US/docs/Web/HTTP/Headers/Content-Security-Policy
• /en-US/docs/Web/HTTP/Headers/Referer
• /en-US/docs/Web/HTTP/Headers/Referrer-Policy

External URLs (8)

URL: /en-US/docs/Web/HTTP/Headers/Content-Security-Policy
Title: Content-Security-Policy

• https://csp.withgoogle.com/docs/strict-csp.html (1 time)
• https://github.com/google/csp-evaluator (1 time)
• https://w3c.github.io/trusted-types/dist/spec/ (2 times)

---

URL: /en-US/docs/Web/HTTP/Headers/Referrer-Policy
Title: Referrer-Policy

• https://blog.mozilla.org/security/2015/01/21/meta-referrer/ (1 time)
• https://en.wikipedia.org/wiki/HTTP_referer (1 time)
• Point default referrer policy to a constant defined in RP spec whatwg/fetch#1066 (1 time)

---

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

• https://blog.mozilla.org/security/2015/01/21/meta-referrer/ (1 time)
• https://en.wikipedia.org/wiki/HTTP_referer (2 times)