message: docs: Fix appHighlightColor typo
  In the example, there's no directive nor input that's named `appHighlightColor`.
  It should be `appHighlight`, referring to the input binding.
  PR Close
diff: @@ -247,7 +247,7 @@ You get the best of both worlds: the property name you want and the binding synt
  <code-example path="attribute-directives/src/app/app.component.html" header="src/app/app.component.html (color)" region="color"></code-example>
  Now that you're binding via the alias to the `highlightColor`, modify the `onMouseEnter()` method to use that property.
  -If someone neglects to bind to `appHighlightColor`, highlight the host element in red:
  +If someone neglects to bind to `appHighlight`, highlight the host element in red:
  <code-example path="attribute-directives/src/app/highlight.directive.3.ts" header="src/app/highlight.directive.ts (mouse enter)" region="mouse-enter"></code-example>
  