docs(*): Document a lot more symbols that are missing comments in our generated docs.

modules/angular2/examples/compiler/ts/url_resolver/url_resolver.ts

@@ -0,0 +1,19 @@
+import {provide} from 'angular2/core';
+import {bootstrap} from 'angular2/bootstrap';
+import {UrlResolver} from 'angular2/compiler';
+
+var MyApp;
+
+// #docregion url_resolver
+class MyUrlResolver extends UrlResolver {
+  resolve(baseUrl: string, url: string): string {
+    // Serve CSS files from a special CDN.
+    if (url.substr(-4) === '.css') {
+      return super.resolve('http://cdn.myapp.com/css/', url);
+    }
+    return super.resolve(baseUrl, url);
+  }
+}
+
+bootstrap(MyApp, [provide(UrlResolver, {useClass: MyUrlResolver})]);
+// #enddocregion