Updated the onchange test's parameter

Updated the onchange test's parameter so it matches the latest definition.

intro.js/intro.js-tests.ts

@@ -50,8 +50,8 @@ intro.start()
     .onafterchange(function (element) {
         element.getAttribute('class');
     })
-    .onchange(function () {
-        alert('Changed');
+    .onchange(function (element) {
+        element.getAttribute('class');
     })
     .oncomplete(function () {
         alert('Done');