GCP Manager manual: use help icon

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@43914 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/docs/wxGUI.GCP_Manager.html

@@ -225,7 +225,7 @@ canvas (source or target).</dd>
   </dl><br>
 </dd>
 
-<dt>
+<dt><img src="icons/grass2/help.png">&nbsp;
 <em>Show Help</em></dt>
 <dd>Show help page for the GCP Manager.