Update Application.php to remove route cache

Also adds note on plugin to add cached routing

Author: umer936

src/Application.php

@@ -86,10 +86,8 @@ public function middleware(MiddlewareQueue $middlewareQueue): MiddlewareQueue
 
             // Add routing middleware.
             // If you have a large number of routes connected, turning on routes
-            // caching in production could improve performance. For that when
-            // creating the middleware instance specify the cache config name by
-            // using it's second constructor argument:
-            // `new RoutingMiddleware($this, '_cake_routes_')`
+            // caching in production could improve performance.
+            // See https://github.com/CakeDC/cakephp-cached-routing
             ->add(new RoutingMiddleware($this))
 
             // Parse various types of encoded request bodies so that they are