docs(toh5): add better explanations for templateUrl

closes #929

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

@@ -10,7 +10,9 @@ import { HeroService } from './hero.service';
 
 @Component({
   selector: 'my-dashboard',
+  // #docregion template-url
   templateUrl: 'app/dashboard.component.html',
+  // #enddocregion template-url
   // #docregion css
   styleUrls: ['app/dashboard.component.css']
   // #enddocregion css

public/docs/ts/latest/tutorial/toh-pt5.jade

@@ -281,8 +281,13 @@ code-example(format="." language="bash").
   Let’s spice up the dashboard by displaying the top four heroes at a glance.
   
   Replace the `template` metadata with a `templateUrl` property that points to a new
-  template file, `dashboard.component.html`.
+  template file.
   
++makeExample('toh-5/ts/app/dashboard.component.ts', 'template-url', 'app/dashboard.component.ts (templateUrl)')(format=".")
+.l-sub-section
+  :marked
+    Even if the template sits on the same folder as the component, the path for the template will be root-relative.
+:marked
   Create that file with these contents:
 +makeExample('toh-5/ts/app/dashboard.component.html', null, 'dashboard.component.html')(format=".")
 :marked
@@ -581,6 +586,7 @@ figure.image-display
   :marked
     The `styleUrls` property is an array of style file names (with paths).
     We could list multiple style files from different locations if we needed them.
+    Like with `templateUrl`, the paths are root-relative.
 :marked
   ### Stylish Hero Details
   The designers also gave us CSS styles specifically for the `HeroDetailComponent`.