angular/angular.js — pull request #5393 by moretti (2013-12-13 14:41:31+00:00)
Title: docs(angular.module): 'MyModule' -> 'myModule'

The module in the example is created in lower camel case:

var myModule = angular.module('myModule', []);

So it should be:

var injector = angular.injector(['ng', 'myModule'])