message: docs: fix typo in upgrade guide
  PR Close
diff: @@ -1709,7 +1709,7 @@ Create a new `app.component.ts` file with the following `AppComponent` class:
  <code-example path="upgrade-phonecat-3-final/app/app.component.ts" header="app/app.component.ts">
  </code-example>
  -It has a simple template that only includes the `<router-outlet>.
  +It has a simple template that only includes the `<router-outlet>`.
  This component just renders the contents of the active route and nothing else.
  The selector tells Angular to plug this root component into the `<phonecat-app>`
  