Merge branch '5.4' into 6.4

* 5.4:
  [PhpUnitBridge][VarDumper] fix color detection
  [CI] Make sure we preserve file->header when we run sync-translations.php
  Review validators.sl.xlf

Author: nicolas-grekas

Diff for: DeprecationErrorHandler.php

@@ -412,13 +412,10 @@ private static function hasColorSupport()
         }
 
         if (!self::isTty()) {
-            return true;
+            return false;
         }
 
-        if ('\\' === \DIRECTORY_SEPARATOR
-            && \function_exists('sapi_windows_vt100_support')
-            && @sapi_windows_vt100_support(\STDOUT)
-        ) {
+        if ('\\' === \DIRECTORY_SEPARATOR && \function_exists('sapi_windows_vt100_support') && @sapi_windows_vt100_support(\STDOUT)) {
             return true;
         }