[spoiler=hidden] <insert text here>[/spoiler]
It actually was noticed and there was a legitimate reason for why it hadn't been fixed and why there was such an atrocious typo in the first place...which I can't recall at the moment.
There should probably be some sort of priority system organizing suggestions. This seems to be fairly low on the food chain. ._.
$txt['spoiler_default_for'] = 'Hiden';