fix: correct sample in file (#19190)

Make the sample code return
the correct type of RouteObject[]
instead of only RouteObject

Fixes #19178

Co-authored-by: Mikhail Shabarov <61410877+mshabarov@users.noreply.github.com>

Author: caalador

flow-server/src/main/resources/com/vaadin/flow/server/frontend/routes.tsx

@@ -41,18 +41,22 @@ export const { router, routes } = new RouterConfigurationBuilder()
     // To define routes manually or adding an individual route, use the
     // following code and remove (1):
     // .withReactRoutes(
-    //     {
+    //     [
+    //       {
     //         element: <MainLayout />,
     //         handle: { title: 'Main' },
     //         children: [
     //             { path: '/hilla', element: <HillaView />, handle: { title: 'Hilla' } }
     //         ],
-    //     },
-    //     { path: '/login', element: <Login />, handle: { title: 'Login' } }
+    //       },
+    //       { path: '/login', element: <Login />, handle: { title: 'Login' } }
+    //     ]
     // )
     // OR
     // .withReactRoutes(
-    //     { path: '/login', element: <Login />, handle: { title: 'Login' } },
+    //   [
+    //     { path: '/login', element: <Login />, handle: { title: 'Login' } }
+    //   ]
     // )
     .withFallback(Flow)
     // Optional method that adds an authentication for routes.