Merge branch '5.3' into 5.4

* 5.3:
  Fix TranslationTrait for multiple domains
  Fix parameter types for ProcessHelper::mustRun()
  Fix: Wording
  Remove return void PHPDoc in test

Helper/ProcessHelper.php

@@ -92,9 +92,9 @@ public function run(OutputInterface $output, $cmd, string $error = null, callabl
      * This is identical to run() except that an exception is thrown if the process
      * exits with a non-zero exit code.
      *
-     * @param string|Process $cmd      An instance of Process or a command to run
-     * @param callable|null  $callback A PHP callback to run whenever there is some
-     *                                 output available on STDOUT or STDERR
+     * @param array|Process $cmd      An instance of Process or a command to run
+     * @param callable|null $callback A PHP callback to run whenever there is some
+     *                                output available on STDOUT or STDERR
      *
      * @return Process
      *