message: docs: fix typo in router.md
  This commit fixes a typo in the router documentation. "Benfits of a routing module" => "Benefits of a routing module"
  PR Close
diff: @@ -579,7 +579,7 @@ The application continues to work just the same, and you can use `AppRoutingModu
  {@a why-routing-module}
  -### Benfits of a routing module
  +### Benefits of a routing module
  The routing module, often called the `AppRoutingModule`, replaces the routing configuration in the root or feature module.
  