note 29180 added to introduction

I find this page (or the anchor for "What is PHP?" at http://www.php.net/manual/en/introduction.php#intro-whatis in particular) very useful in answering novice question about PHP and/or our site design (which has just started using PHP). Thanks for putting up all these in a simple and idiot-proof manner. -- http://www.php.net/manual/en/introduction.php http://master.php.net/manage/user-notes.php?action=edit+29180 http://master.php.net/manage/user-notes.php?action=delete+29180 http://master.php.net/manage/user-notes.php?action=reject+29180