typo in icon name

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@41587 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/docs/wxGUI.Icons.html

@@ -213,7 +213,7 @@ Currently are supported three icon theme sets:
 	  <td><img src="icons/grass/module-d.histogram.gif"></td>
 	</tr>
 	<tr>
-	  <td><img src="icons/grass2/element-add.png"></td>
+	  <td><img src="icons/grass2/overlay-add.png"></td>
 	  <td><img src="icons/silk/overlays.png"></td>
 	  <td><img src="icons/grass/gui-rastanalyze.gif"></td>
 	</tr>