message: docs(aio): typo fix
  tutorial part 0 app component template file extention fix
  PR Close
diff: @@ -62,7 +62,7 @@ Open the component class file (`app.component.ts`) and change the value of the `
  <code-example path="toh-pt0/src/app/app.component.ts" region="set-title" title="app.component.ts (class title property)" linenums="false">
  </code-example>
  -Open the component template file (`app.component.ts`) and
  +Open the component template file (`app.component.html`) and
  delete the default template generated by the Angular CLI.
  Replace it with the following line of HTML.
  