docs: add correct default cli ngModule (#31166)

PR Close #31166

aio/content/examples/ngmodules/src/app/app.module.1.ts

@@ -0,0 +1,14 @@
+// imports
+import { BrowserModule } from '@angular/platform-browser';
+import { NgModule } from '@angular/core';
+
+import { AppComponent } from './app.component';
+
+// @NgModule decorator with its metadata
+@NgModule({
+  declarations: [AppComponent],
+  imports: [BrowserModule],
+  providers: [],
+  bootstrap: [AppComponent]
+})
+export class AppModule {}