docs(README): fix sample location in Dart

Closes angular#745

Author: kevmoo

README.md

@@ -85,7 +85,7 @@ source `modules/examples/src/hello_world/index.js`.
 
 You can build this example as either JS or Dart app:
 * (JS) `gulp serve.js.dev` and open `localhost:8000/examples/src/hello_world/` in Chrome.
-* (Dart) `gulp serve/examples.dart` and open `localhost:8080/hello_world` in Chrome (for dart2js) or Dartium (for Dart VM).
+* (Dart) `gulp serve/examples.dart` and open `localhost:8080/src/hello_world` in Chrome (for dart2js) or Dartium (for Dart VM).
 
 ## Debug the transpiler