fixed typo

Author: pchampin

index.html

@@ -1618,7 +1618,7 @@ <h3>Algorithm</h3>
               <code>@prefix</code> <a>entry</a>, which MUST be a <a>boolean</a>. Otherwise, an
               <a data-link-for="JsonLdErrorCode">invalid @prefix value</a>
               error has been detected and processing is aborted.</li>
-            <li>If the <a>prefix flag</a> of <var>definition</var>is set to true,
+            <li>If the <a>prefix flag</a> of <var>definition</var>is set to <code>true</code>,
               and its <a>IRI mapping</a> is a <a>keyword</a>,
               an <a data-link-for="JsonLdErrorCode">invalid term definition</a>
               has been detected and processing is aborted.</li>