Improve documentation for default_charset in PHP 5.6.


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@334627 c90b9560-bf6c-de11-be94-00142212c4b1
Note php://input's reusability in PHP 5.6.


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@334628 c90b9560-bf6c-de11-be94-00142212c4b1