[PHP-DOC] xmlwriter versions.xml : need to fix version for 3 functions

[Laurent Laville]

PHP 5 Changelog  http://www.php.net/ChangeLog-5.php#5.2.1, gave us these 
informations

Added three new functions to ext/xmlwriter (Rob, Ilia)
    * xmlwriter_start_dtd_entity()
    * xmlwriter_end_dtd_entity()
    * xmlwriter_write_dtd_entity()


So it should be fix into
http://cvs.php.net/viewvc.cgi/phpdoc/en/reference/xmlwriter/versions.xml

That show version 5.1.2 rather than 5.2.1