Trailing spaces removed

Author: snowcore

src/guides/v2.3/howdoi/checkout/checkout_new_step.md

@@ -215,16 +215,16 @@ Create a mixin as follows:
        'use strict';
 
        var mixin = {
-   
+
            initialize: function () {
                // set visible to be initially false to have your step show first
                this.isVisible = ko.observable(false);
                this._super();
-   
+
                return this;
            }
        };
-   
+
        return function (target) {
            return target.extend(mixin);
        };