8260462: Missing <thead> in Modality.html

Reviewed-by: serb, psadhukhan

Author: aivanov-jdk

src/java.desktop/share/classes/java/awt/doc-files/Modality.html

@@ -208,14 +208,14 @@ <h2>Show/hide blocking</h2>
 
           <table class="striped">
 	        <caption>The Standard Blocking Matrix</caption>
-            <tbody><tr>
+            <thead><tr>
               <th scope="col">current/shown</th>
               <th scope="col">frame &amp; modeless</th>
               <th scope="col">document</th>
               <th scope="col">application</th>
               <th scope="col">toolkit</th>
-            </tr>
-            <tr>
+            </tr></thead>
+            <tbody><tr>
               <th scope="row">-</th>
               <td>-</td>
               <td>-</td>