Update references to HTTP. (#518)

* Update references

* Update references to use data-cite

Author: markafoltz

index.html

@@ -297,16 +297,10 @@ <h2>
         as defined in [[!ECMASCRIPT]].
       </p>
       <p>
-        The header <dfn>Accept-Language</dfn> is used as <a href=
-        "https://tools.ietf.org/html/rfc7231#section-5.3.5" title=
-        "Definition of Accept-Language in HTTP/1.1">defined in HTTP/1.1</a>
-        [[!rfc7231]].
-      </p>
-      <p>
-        <dfn>HTTP authentication</dfn> is used as <a href=
-        "https://tools.ietf.org/html/rfc7235#section-2" title=
-        "Definition of HTTP authentication in HTTP/1.1: Authentication">defined
-        in HTTP/1.1: Authentication</a> [[!rfc7235]].
+        The terms <dfn data-cite=
+        "rfc9110#section-12.5.4">Accept-Language</dfn> and <dfn data-cite=
+        "rfc9110#section-11">HTTP authentication</dfn> are used as defined in
+        [[!RFC9110]].
       </p>
       <p>
         The term <dfn>cookie store</dfn> is used as <a href=