substr length broken

[mmoskal]

let str = "A very long string hey ho hey ho"
game.onPaint(function () {
    screen.print(str.substr(6), 0, 0)
})

This prints long stri as the length in substr() defaults to 10...

[mmoskal]

we could move substr() to helpers and implement with slice() (which doesn't have the issue)

[mmoskal]

cc @gitri-ms