Fixed javadoc typos.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1462485 13f79535-47bb-0310-9956-ffa450edef68
Small edits.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1462487 13f79535-47bb-0310-9956-ffa450edef68