Fix missing discount label in checkout

Fix js static test

(cherry picked from commit 0f36e0e)

Author: ihor-sviziev

app/code/Magento/SalesRule/view/frontend/web/js/view/summary/discount.js

@@ -47,10 +47,11 @@ define([
         /**
          * Get discount title
          *
-         * @returns {null|string}
+         * @returns {null|String}
          */
         getTitle: function () {
             var discountSegments;
+
             if (!this.totals()) {
                 return null;
             }