fix CI

Author: zairigimad

mailer.rst

@@ -640,6 +640,7 @@ and it will select the appropriate certificate depending on the ``To`` option::
     $secondEncryptedEmail = $encrypter->encrypt($secondEmail);
 
 .. tip::
+
     The ``SMimeEncrypter`` class defines a second argument to choose
     an algorithm to encrypt the message. the cipher must be one of these PHP constants: https://www.php.net/manual/en/openssl.ciphers.php