Fix indentation

lib/browser/guest-window-manager.js

@@ -141,7 +141,7 @@ const getGuestWindow = function (guestId) {
 ipcMain.on('ELECTRON_GUEST_WINDOW_MANAGER_WINDOW_OPEN', function (event, url, frameName, disposition, options, additionalFeatures) {
   options = mergeBrowserWindowOptions(event.sender, options)
   event.sender.emit('new-window', event, url, frameName, disposition, options, additionalFeatures)
-  var newGuest = event.newGuest
+  const newGuest = event.newGuest
   if ((event.sender.isGuest() && !event.sender.allowPopups) || event.defaultPrevented) {
     if (newGuest != undefined && newGuest != null) {
       event.returnValue = setupGuest(event.sender, frameName, newGuest)