Pre -> code to make links work (#291)

Author: noamr

index.html

@@ -907,11 +907,11 @@ <h4>
             by the following ABNF [[RFC5234]] (using <a data-cite=
             "RFC7230#section-7">List Extension</a>, [[RFC7230]]):
           </p>
-          <pre class="abnf">
-            Timing-Allow-Origin = 1#( <a data-cite=
-"FETCH#origin-header">origin-or-null</a> / <a data-cite=
-"FETCH#http-new-header-syntax">wildcard</a> )
-          </pre>
+          <code class="abnf">
+            Timing-Allow-Origin = 1#( <a
+            data-cite="FETCH#origin-header">origin-or-null</a> / <a
+            data-cite="FETCH#http-new-header-syntax">wildcard</a> )
+          </code>
           <p>
             The sender MAY generate multiple <a>Timing-Allow-Origin</a> header
             fields. The recipient MAY combine multiple