message: docs: fix typo in deployment guide
  The typo causes most of the callout to not appear on the page. The issue
  appears at the bottom of the "Lazy loading" section on the live site:
  PR Close
diff: @@ -304,7 +304,7 @@ Configure the Angular Router to defer loading of all other modules (and their as
  or by [_lazy loading_](guide/router#asynchronous-routing "Lazy loading")
  them on demand.
  -<div class="callout is-helpful>
  +<div class="callout is-helpful">
  <header>Don't eagerly import something from a lazy-loaded module</header>
  