docs: Update wildcard route component to PageNotFoundComponent (#54570)

This PR enhances the Angular documentation by replacing the placeholder `<component-name>` with the actual `PageNotFoundComponent` in the wildcard route configuration. This update ensures that the documentation accurately reflects the recommended practice for handling page-not-found scenarios. Additionally, it addresses the issue where HTML entities like `&lt;` were being displayed instead of the desired `<` symbol, resulting in clearer and more readable documentation for users.
PR Close #54570

aio/content/guide/router.md

@@ -184,7 +184,7 @@ The Angular router selects this route any time the requested URL doesn't match a
 To set up a wildcard route, add the following code to your `routes` definition.
 
 ```
-{ path: '**', component: <component-name> }
+{ path: '**', component: PageNotFoundComponent }
 ```
 
 The two asterisks, `**`, indicate to Angular that this `routes` definition is a wildcard route.