Replace optionNal to optional

src/Symfony/Component/HttpKernel/Log/DebugLoggerInterface.php

@@ -23,7 +23,7 @@ interface DebugLoggerInterface
      *
      * A log is an array with the following mandatory keys:
      * timestamp, message, priority, and priorityName.
-     * It can also have an optionnal context key containing an array.
+     * It can also have an optional context key containing an array.
      *
      * @return array An array of logs
      */