[Mailer] Minor reformating

Page: https://symfony.com/doc/6.4/mailer.html#message-headers Reason: Code block too wide by one word ;-)
symfony · javiereguiluz · Feb 6, 2025 · Feb 6, 2025 · Feb 6, 2025 · a95a58058d0940d2c178604fa0eaadb90d6b2cae
commit a95a58058d0940d2c178604fa0eaadb90d6b2cae
diff --git a/mailer.rst b/mailer.rst
@@ -572,8 +572,8 @@ header, etc.) but most of the times you'll set text headers::

    $email = (new Email())
        ->getHeaders()
-            // this non-standard header tells compliant autoresponders ("email holiday mode") to not
-            // reply to this message because it's an automated email
+            // this non-standard header tells compliant autoresponders ("email holiday mode")
+            // to not reply to this message because it's an automated email
            ->addTextHeader('X-Auto-Response-Suppress', 'OOF, DR, RN, NRN, AutoReply')

            // use an array if you want to add a header with multiple values