Fixed typo in tutorial(Routing)

The path to `app.component.css` should start from current directory, not 'app/', since the file is already in 'app/'

Author: timxzz

public/docs/_examples/toh-5/ts/app/app.component.ts

@@ -14,7 +14,7 @@ import { Component } from '@angular/core';
   `,
   // #enddocregion template
   // #docregion styleUrls
-  styleUrls: ['app/app.component.css'],
+  styleUrls: ['app.component.css'],
   // #enddocregion styleUrls
 })
 export class AppComponent {