Event list only has first line of PHP event description

Presently, there are 16 events that have more than one line of description text, but the event extractor only fetches the first.

Example:

https://wiki.phpbb.com/Event_List#core.viewtopic_add_quickmod_option_before

https://github.com/phpbb/phpbb/blob/release-3.2.2/phpBB/viewtopic.php#L621-L622