web/index: make preset label th

Author: rkdarst

web/index.html

@@ -80,7 +80,7 @@
 
     <table border="1">
         <tr>
-            <td rowspan="3" title="Presets allow you to give a name to a {scene, resolution} combination and jump directly there.  Recommended to make scenes configured for each instructor.  Note they still have to screenshare on Zoom.">Scene presets:</td>
+            <th rowspan="3" title="Presets allow you to give a name to a {scene, resolution} combination and jump directly there.  Recommended to make scenes configured for each instructor.  Note they still have to screenshare on Zoom.">Scene presets:</th>
             <td><button class="preset-go"           id="preset-a">Go</button></td>
             <!--<td><button class="preset-label synced" id="preset-a" syncwith="preset-preset-a-label">A</button></td>-->
             <td><input  class="preset-label synced" id="preset-a" type="text" syncwith="preset-preset-a-label" value="A" size="10"></td>