Is there anyway to get a newline into a tooltip?

I'm really loving the speed of css3 tooltips over the likes of tippyjs that I would normally use (Though I still need to use something like tippy or bootstraps tooltips if I want HTML in a tooltip), but for a lot of the basic stuff, this library works perfectly.

However, for some reason, I can't get 
 to work.

In a regular 'title' attribute, I can do something like

title="test
test2"

and the tooltip when it shows will have 'test2' on the line below 'test'.