docs: replace lazy loading import syntax parameter name (#34599)

We replace `mod` with `m` to be in line with what the CLI generates.

PR Close #34599

aio/content/examples/lazy-loading-ngmodules/src/app/app-routing.module.ts

@@ -8,12 +8,12 @@ import { Routes, RouterModule } from '@angular/router';
 const routes: Routes = [
   {
     path: 'customers',
-    loadChildren: () => import('./customers/customers.module').then(mod => mod.CustomersModule)
+    loadChildren: () => import('./customers/customers.module').then(m => m.CustomersModule)
     // #enddocregion routes-customers
   },
   {
     path: 'orders',
-    loadChildren: () => import('./orders/orders.module').then(mod => mod.OrdersModule)
+    loadChildren: () => import('./orders/orders.module').then(m => m.OrdersModule)
     // #enddocregion routes-customers-orders
   },
   {