s/Underscore/_

IPython/html/static/notebook/js/widgetmanager.js

@@ -23,7 +23,7 b''
     // elsewhere.
     define(["underscore",
              "backbone",
-            ], function (Underscore, Backbone) {
+            ], function (_, Backbone) {
 
         //--------------------------------------------------------------------
         // WidgetManager class

IPython/html/static/notebook/js/widgets/widget.js

@@ -17,7 +17,7 b''
 define(["notebook/js/widgetmanager",
         "underscore",
         "backbone"], 
-function(WidgetManager, Underscore, Backbone){
+function(WidgetManager, _, Backbone){
 
     var WidgetModel = Backbone.Model.extend({
         constructor: function (widget_manager, model_id, comm) {