Replaced the traditional function expressions with ES6 arrow function expressions in the JavaScript for the transaction order, account order, currency form, and the speed dial for the material floating action buttons.

src/accounting/static/js/account-order.js

@@ -22,10 +22,10 @@
  */
 
 // Initializes the page JavaScript.
-document.addEventListener("DOMContentLoaded", function () {
+document.addEventListener("DOMContentLoaded", () => {
     const list = document.getElementById("accounting-order-list");
     if (list !== null) {
-        const onReorder = function () {
+        const onReorder = () => {
             const accounts = Array.from(list.children);
             for (let i = 0; i < accounts.length; i++) {
                 const no = document.getElementById("accounting-order-" + accounts[i].dataset.id + "-no");