message: tweak code style
diff: @@ -250,12 +250,10 @@ class ZRender {
  this._stillFrameAccum = 0;
  this.trigger('rendered');
  }
  - else {
  + else if (this._sleepAfterStill > 0) {
  this._stillFrameAccum++;
  -
  - const sleepAfterStill = this._sleepAfterStill;
  // Stop the animiation after still for 10 frames.
  - if (sleepAfterStill > 0 && this._stillFrameAccum > sleepAfterStill) {
  + if (this._stillFrameAccum > this._sleepAfterStill) {
  this.animation.stop();
  }
  }
  