[MCHECKSTYLE-234] group rules by category

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1621644 13f79535-47bb-0310-9956-ffa450edef68
don't repeat category, for better readability

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1621646 13f79535-47bb-0310-9956-ffa450edef68
remove bold display for rule parameter names

git-svn-id: https://svn.apache.org/repos/asf/maven/plugins/trunk@1621647 13f79535-47bb-0310-9956-ffa450edef68