fixed link

git-svn-id: https://svn.apache.org/repos/asf/maven/doxia/doxia-sitetools/trunk@1621468 13f79535-47bb-0310-9956-ffa450edef68
better explanations

git-svn-id: https://svn.apache.org/repos/asf/maven/doxia/doxia-sitetools/trunk@1621469 13f79535-47bb-0310-9956-ffa450edef68