identation requirement to eslint

src/editor/EditorStartup.js

@@ -255,8 +255,8 @@ class EditorStartup {
     });
 
     function addListenerMulti(element, eventNames, listener) {
-      var events = eventNames.split(' ');
-      for (var i=0, iLen=events.length; i<iLen; i++) {
+      let events = eventNames.split(' ');
+      for (let i=0, iLen=events.length; i<iLen; i++) {
         element.addEventListener(events[i], listener, false);
       }
     }