message: Missed the removes
  also fix more indenting
diff: @@ -131,11 +131,12 @@ export default class UserActivity {
  * Stop tracking user activity
  */
  stop() {
  - this._document.onmousedown = undefined;
  - this._document.onmousemove = undefined;
  - this._document.onkeydown = undefined;
  - this._window.removeEventListener('wheel', this._onUserActivity,
  - { passive: true, capture: true });
  + this._document.removeEventListener('mousedown', this._onUserActivity);
  + this._document.removeEventListener('mousemove', this._onUserActivity);
  + this._document.removeEventListener('keydown', this._onUserActivity);
  + this._window.removeEventListener('wheel', this._onUserActivity, {
  + passive: true, capture: true,
  + });
  this._document.removeEventListener("visibilitychange", this._onPageVisibilityChanged);
  this._window.removeEventListener("blur", this._onWindowBlurred);
  