better variable names in example

Based on old user note from Martin

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@335140 c90b9560-bf6c-de11-be94-00142212c4b1
basic example of libxml error handling for xslt (doc bug #55360)

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@335141 c90b9560-bf6c-de11-be94-00142212c4b1
auto_populate_raw_post_data generates E_DEPRECATED when *used* (doc bug #67991)

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@335142 c90b9560-bf6c-de11-be94-00142212c4b1