message: docs: add a note for use functional component
diff: @@ -857,6 +857,18 @@ Route record that can be provided by the user when adding routes via the [`route
  - **See Also**: [Meta fields](../guide/advanced/meta.md)
  +:::tip
  +If you want to use a functional component, make sure to add a `displayName` to it.
  +
  +For example:
  +```js
  +const HomeView = () => h('div', 'HomePage')
  +// in TypeScript, you will need to use the FunctionalComponent type
  +HomeView.displayName = 'HomeView'
  +const routes = [{ path: '/', component: HomeView }]
  +```
  +:::
  +
  ## RouteRecordNormalized
  Normalized version of a [Route Record](#routerecordraw)
  