message: docs(observable): fix example
  Fix a small typo in one of the examples
diff: @@ -405,7 +405,7 @@ Each Observable must define how to dispose resources of that execution when we c
  For instance, this is how we clear an interval execution set with `setInterval`:
  ```js
  -var observable = Rx.Observable.create(function subscribe(observer) {
  +var observable = Observable.create(function subscribe(observer) {
  // Keep track of the interval resource
  var intervalID = setInterval(() => {
  observer.next('hi');
  