Updated custom.js template to reflect IPython namespace changes

IPython/html/static/custom/custom.js

@@ -17,7 +17,7 @@
  * Create a custom button in toolbar that execute `%qtconsole` in kernel
  * and hence open a qtconsole attached to the same kernel as the current notebook
  *
- *    $([IPython.events]).on('app_initialized.NotebookApp', function(){
+ *    IPython.events.on('app_initialized.NotebookApp', function(){
  *        IPython.toolbar.add_buttons_group([
  *            {
  *                 'label'   : 'run qtconsole',
@@ -35,7 +35,7 @@
  * At the completion of the dashboard loading, load an unofficial javascript extension
  * that is installed in profile/static/custom/ 
  *
- *    $([IPython.events]).on('app_initialized.DashboardApp', function(){
+ *    IPython.events.on('app_initialized.DashboardApp', function(){
  *        require(['custom/unofficial_extension.js'])
  *    });
  *