add a legend to the left nav

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@115807 13f79535-47bb-0310-9956-ffa450edef68

xdoc/plugin.properties

@@ -27,6 +27,8 @@ maven.xdoc.crumb.separator=|
 maven.xdoc.theme.url=
 maven.xdoc.theme=theme
 
+maven.xdoc.legend=true
+
 # Location where the artifacts are distributed. This property is optional. 
 # If it is not defined, then the Download report will not be added to the 
 # navigation menu.