docs

* SQLTemplate - finishing touches
(cherry picked from commit 143216d9658275e28382a1b40df40a1e1b9a07cc)

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/branches/STABLE-3.1@1447806 13f79535-47bb-0310-9956-ffa450edef68