message: docs(animations): remove duplicate word
diff: @@ -496,7 +496,7 @@ those callbacks like this:
  -The callbacks receive an `AnimationEvent` that contains contains useful properties such as
  +The callbacks receive an `AnimationEvent` that contains useful properties such as
  `fromState`, `toState` and `totalTime`.
  Those callbacks will fire whether or not an animation is picked up.
  