Small parenthesis fix in the Usage Guide

Author: carlosame

usage.html

@@ -1013,7 +1013,7 @@ <h2><code>@supports</code> rules</h2>
 <p>It is possible to use the object model to access the <code>@supports</code> conditions, which work in a similar way to Media Queries (but with <a class="codeitem"
 href="api/latest/io.sf.carte.css4j/io/sf/carte/doc/style/css/nsac/DeclarationCondition.html">DeclarationCondition</a>
 instead of <a class="codeitem" href="api/latest/io.sf.carte.css4j/io/sf/carte/doc/style/css/MediaQueryPredicate.html">MediaQueryPredicate</a>
-objects as predicates.</p>
+objects as predicates).</p>
 <p>For example:</p>
 <pre class="code"><code class="language-java">// Instantiate a css factory (we could also obtain it from a
 // pre-existing css4j object)