message: docs: fix typo in tag name (`my-child` --> `app-child`)
  Fixes
  PR Close
diff: @@ -561,7 +561,7 @@ the `AfterContentComponent`'s parent. Here's the parent's template:
  <code-example path="lifecycle-hooks/src/app/after-content.component.ts" region="parent-template" title="AfterContentParentComponent (template excerpt)" linenums="false"></code-example>
  -Notice that the `<my-child>` tag is tucked between the `<after-content>` tags.
  +Notice that the `<app-child>` tag is tucked between the `<after-content>` tags.
  Never put content between a component's element tags *unless you intend to project that content
  into the component*.
  @@ -571,7 +571,7 @@ Now look at the component's template:
  The `<ng-content>` tag is a *placeholder* for the external content.
  It tells Angular where to insert that content.
  -In this case, the projected content is the `<my-child>` from the parent.
  +In this case, the projected content is the `<app-child>` from the parent.
  <figure>
  <img src='generated/images/guide/lifecycle-hooks/projected-child-view.png' alt="Projected Content">
  