Merge branch '5.4' into 6.0

* 5.4:
  Update ExceptionInterface.php
  Revert removal of Stringable check
  Flush with flush() after ob_end_flush()
  [Validator] : Fix "PHP Warning: Undefined array key 1" in NotCompromisedPasswordValidator
  [Validator] Fix traverse option on Valid constraint when used as Attribute
  [HttpFoundation] Fix deleteFileAfterSend on client abortion
  Prevent that bad Ignore method annotations lead to incorrect results
  also fix the test
  fix deprecation
  fix sending request to paths containing multiple slashes
  Fix generated validation error message for wrong exception mapping status code

Author: derrabus

DependencyInjection/Configuration.php

@@ -1207,7 +1207,7 @@ private function addExceptionsSection(ArrayNodeDefinition $rootNode)
                                 ->info('The status code of the response. Null to let Symfony decide.')
                                 ->validate()
                                     ->ifTrue(function ($v) { return $v < 100 || $v > 599; })
-                                    ->thenInvalid('The log level is not valid. Pick a value between 100 and 599.')
+                                    ->thenInvalid('The status code is not valid. Pick a value between 100 and 599.')
                                 ->end()
                                 ->defaultNull()
                             ->end()