message: docs: update example hero ID
  The hero ID "11" does not correspond to any hero from the example mock heroes list described at ID 12 seems to be the more fitting ID to get the hero with name "Dr. Nice".
  PR Close
diff: @@ -319,7 +319,7 @@ Here's the class after pruning away the dead code.
  Previously, the parent `HeroesComponent` set the `HeroDetailComponent.hero` property and the `HeroDetailComponent` displayed the hero.
  `HeroesComponent` doesn't do that anymore.
  -Now the router creates the `HeroDetailComponent` in response to a URL such as `~/detail/11`.
  +Now the router creates the `HeroDetailComponent` in response to a URL such as `~/detail/12`.
  The `HeroDetailComponent` needs a new way to obtain the hero-to-display.
  This section explains the following:
  @@ -389,7 +389,7 @@ You'll be able to re-implement `getHero()` as a real `Http` request without havi
  The browser refreshes and the application is working again.
  You can click a hero in the dashboard or in the heroes list and navigate to that hero's detail view.
  -If you paste `localhost:4200/detail/11` in the browser address bar, the router navigates to the detail view for the hero with `id: 11`, "Dr Nice".
  +If you paste `localhost:4200/detail/12` in the browser address bar, the router navigates to the detail view for the hero with `id: 12`, "Dr Nice".
  <a id="goback"></a>
  