add .html

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1523397 13f79535-47bb-0310-9956-ffa450edef68
add more extensions

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1523398 13f79535-47bb-0310-9956-ffa450edef68