Docs: event.preventDefault() and event.stopPropagation() not existing

[cookiengineer]

Minor issue: The docs seem to be outdated when it comes to the NMLEvent or NidiumEvent.

For these cases there's no event.preventDefault() and no event.stopPropagation() methods (just in case some people are wondering or are using libraries that would expect those to exist):

• window._onkeydown
• window._onmousedown
• window._onmousemove
• window._onmouseup

It might make sense to link the docs to the NidiumEvent or NMLEvent, depending on what is used there - e.g. NidiumEvent - to prevent confusion.