docs: replace code line

aio/content/tutorial/toh-pt4.md

@@ -97,10 +97,11 @@ in the `HeroesComponent`, in the `AppComponent`, in the `AppModule`. You could h
 
 By default, the Angular CLI command `ng generate service` registers a provider with the _root injector_ for your service. When you provide it at the root level, Angular creates a single, shared instance of HeroService and injects into any class that asks for it. You can modify this and register your service at different levels (HeroesComponent, AppModule) based on your use case.
 
-The `@Injectable()` decorator accepts a metadata object for the service, the same way the `@Component()` decorator did for your component classes. One of the metadata values specifies that this class provides the defined service at one of the available levels. If you look at the `@Injectable()` statement right before the `HeroService` class definition, you can see that the `providedIn` metadata value is "root":    
+The `@Injectable()` decorator accepts a metadata object for the service, the same way the `@Component()` decorator did for your component classes. One of the metadata values specifies that this class provides the defined service at one of the available levels. If you look at the `@Injectable()` statement right before the `HeroService` class definition, you can see that the `providedIn` metadata value is `root`:    
 
-<code-example path="toh-pt4/src/app/hero.service.2.ts" linenums="false" title="src/app/app.service.ts (provide service)" region="provider">
-</code-example>
+```
+@Injectable({providedIn: root})
+```
 
 When you provide a service at the root level, Angular creates a single, shared instance of `HeroService` and injects into any class that asks for it.