Fix punctuation

Co-authored-by: Ted Thibodeau Jr <[email protected]>

Author: 2 people

index.html

@@ -1667,7 +1667,7 @@ <h3>Algorithm</h3>
               <code>true</code>.</li>
           </ol>
         </li>
-        <li>Otherwise if <var>value</var> contains the <a>entry</a> <code>@id</code> and its value
+        <li>Otherwise, if <var>value</var> contains the <a>entry</a> <code>@id</code> and its value
           does not equal <var>term</var>:
           <ol>
             <li id="ctd-id-null">If the <code>@id</code> <a>entry</a> of <var>value</var>