Missing description in messenger:setup-transports command

making `bin/console` to show an empty description when the rest of the commands have one.

src/Symfony/Component/Messenger/Command/SetupTransportsCommand.php

@@ -41,6 +41,7 @@ class SetupTransportsCommand extends Command
     {
         $this
             ->addArgument('transport', InputArgument::OPTIONAL, 'Name of the transport to setup', null)
+            ->setDescription('Prepares the required infrastructure for the transport')
             ->setHelp(<<<EOF
 The <info>%command.name%</info> command setups the transports: