[bug] calling tween.stop() does not cause tween.update() to return false

Calling tween.stop() should stop the tween, and a following tween.update(time) (f.e. in an animation frame) should return false so that the return value is reliable for exiting the animation loop. Currently this will fail:

function loop(time) {
  const keepGoing = tween.update(time)
  if (keepGoing) requestAnimationFrame(loop)
}

loop(performance.now())

// ... later, before the animation is finished ...
tween.stop() // Does not cause the loop to stop, the loop keeps going.

The tween.stop() call should cause tween.update() to return true so that the animation loop will end.

Start at the tween.stop() and tween.update(time) entry points described in the issue and trace how stopped tweens affect the update return value. Resolve the contradictory wording about returning false versus true, then verify that calling stop before completion produces the intended value for ending the animation loop.