Apply suggestions from code review

Co-authored-by: othercorey <corey.taylor.fl@gmail.com>

Author: ADmad

en/appendices/6-0-migration-guide.rst

@@ -77,7 +77,8 @@ Event
 
 - The signature of ``EventManagerInterface::on()`` has changed. The 2nd and 3rd
   parameters have been swapped. Calls which pass an options array as the 2nd
-  argument will need to be updated to pass it as the 3rd argument instead.
+  argument will need to be updated to pass it as the 3rd argument instead or 
+  use named parameters.
 
 Datasource
 ----------

en/core-libraries/events.rst

@@ -412,7 +412,7 @@ for event listeners::
     $callback = [$this, 'doSomething'];
     $this->getEventManager()->on(
         'Order.afterPlace',
-        $callback
+        $callback,
         ['priority' => 2],
     );