update grass-gxm.dtd (comment added)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@58526 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/xml/grass-gxm.dtd

@@ -18,12 +18,16 @@
 
 <!--    an action defines action properties (usually GRASS modules)
 -->
-<!ELEMENT action (task)>
+<!ELEMENT action (comment?, task)>
 <!ATTLIST action id	CDATA #REQUIRED>
 <!ATTLIST action name	CDATA #REQUIRED>
 <!ATTLIST action pos	CDATA #REQUIRED>
 <!ATTLIST action size	CDATA #REQUIRED>
 
+<!--    action comment
+-->
+<!ELEMENT comment         (#PCDATA)>
+
 <!--	a task describes the interface of a single
 	GRASS command
 -->