start to write up more of internals doc

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@330034 c90b9560-bf6c-de11-be94-00142212c4b1
correction

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@330035 c90b9560-bf6c-de11-be94-00142212c4b1