Editorial: use %s ABNF notation

Fixes #845.

Author: annevk

fetch.bs

@@ -158,7 +158,8 @@ Streams, and URL Standards.
 [[!STREAMS]]
 [[!URL]]
 
-<p><dfn>ABNF</dfn> means ABNF as modified by HTTP (in particular the addition <code>#</code>).
+<p><dfn>ABNF</dfn> means ABNF as augmented by HTTP (in particular the addition <code>#</code>) and
+RFC 7405. [[!RFC7405]]
 
 <hr>
 
@@ -2370,7 +2371,7 @@ compatibility constraints it is not included in all
 <pre>
 Origin                           = origin-or-null
 
-origin-or-null                   = origin / %x6E.75.6C.6C ; "null", case-sensitive
+origin-or-null                   = origin / %s"null" ; case-sensitive
 origin                           = <a for=url>scheme</a> "://" <a for=url>host</a> [ ":" <a for=url>port</a> ]</pre>
 
 <p class="note no-backref">This supplants the `<code>Origin</code>`
@@ -2507,7 +2508,7 @@ Access-Control-Request-Headers   = 1#<a spec=http>field-name</a>
 
 wildcard                         = "*"
 Access-Control-Allow-Origin      = origin-or-null / wildcard
-Access-Control-Allow-Credentials = %x74.72.75.65 ; "true", case-sensitive
+Access-Control-Allow-Credentials = %s"true" ; case-sensitive
 Access-Control-Expose-Headers    = #<a spec=http>field-name</a>
 Access-Control-Max-Age           = <a spec=http-caching>delta-seconds</a>
 Access-Control-Allow-Methods     = #<a spec=http>method</a>
@@ -2982,7 +2983,7 @@ response <a for=/>header</a> can be used to require checking a <a for=/>request<
 <p>Its <a for=header>value</a> <a>ABNF</a>:
 
 <pre>
-Cross-Origin-Resource-Policy     = %x73.61.6D.65.2D.6F.72.69.67.69.6E / %x73.61.6D.65.2D.73.69.74.65 ; "same-origin" / "same-site", case-sensitive</pre>
+Cross-Origin-Resource-Policy     = %s"same-origin" / %s"same-site" ; case-sensitive</pre>
 
 <p>To perform a <dfn>cross-origin resource policy check</dfn>, given a <var>request</var> and
 <var>response</var>, run these steps:</p>