fix spec build (#1504)

Author: linnan-github

index.bs

@@ -62,6 +62,7 @@ spec: structured header; type: dfn; urlPrefix: https://httpwg.org/specs/rfc8941;
         text: token; url: #token
 spec: infra; type: dfn; urlPrefix: https://infra.spec.whatwg.org/
     text: starts with; url: #string-starts-with
+    text: byte sequence; url: #byte-sequence
 spec: fenced-frame; type: dfn; urlPrefix: https://wicg.github.io/fenced-frame/;
     for: navigable
         text: top-level traversable; url: #navigable-top-level-traversable
@@ -70,6 +71,11 @@ spec: fenced-frame; type: dfn; urlPrefix: https://wicg.github.io/fenced-frame/;
 spec: multipage; type: dfn; urlPrefix: https://html.spec.whatwg.org/multipage/;
     for: scheme and host
         text: host; url: #concept-scheme-and-host-host
+spec: url; type: dfn; urlPrefix: https://url.spec.whatwg.org
+    text: url; url: #concept-url
+spec: fetch; type: dfn; urlPrefix: https://fetch.spec.whatwg.org
+    text: fetch; url: #concept-fetch
+    text: request; url: #concept-request
 </pre>
 <pre class=biblio>
 {