message: remove . before map operator inside pipe
diff: @@ -29,7 +29,7 @@ What we do here is mapping a click event to a state changing function. So instea
  ```js
  var increaseButton = document.querySelector('#increase');
  var increase = Rx.Observable.fromEvent(increaseButton, 'click').pipe(
  - .map(() => state => Object.assign({}, state, {count: state.count + 1}))
  + map(() => state => Object.assign({}, state, {count: state.count + 1}))
  );
  // We create an object with our initial state. Whenever a new state change function
  