fix fileformats documentation bug

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_5@1523528 13f79535-47bb-0310-9956-ffa450edef68
add missing @link

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene_solr_4_5@1523531 13f79535-47bb-0310-9956-ffa450edef68