build(aio): change examples to CLI (#19248)

PR Close #19248

aio/content/examples/docs-style-guide/src/main.ts

@@ -1,4 +1,12 @@
 // #docregion
+import { enableProdMode } from '@angular/core';
 import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
+
 import { AppModule } from './app/app.module';
+import { environment } from './environments/environment';
+
+if (environment.production) {
+  enableProdMode();
+}
+
 platformBrowserDynamic().bootstrapModule(AppModule);