Mouse events don't register when palmcheck is enabled


Spent a little while figuring this out but mouse events don’t register with keys held down when palmcheck is enabled in the mouse driver (this is on windows. yet to test on linux/mac).

Likely this isn’t something you can’t fix/is nothing to do with SDL2 itself as it’s being done on a driver level, but it would be useful to others (and future me, i’m forgetful) if this could be mentioned in the docs/wiki.