Merge branch '6.1' into 6.2

* 6.1:
  Recommending "strict" mode for users of Symfony Mailer

Author: javiereguiluz

reference/constraints/Email.rst

@@ -128,15 +128,17 @@ This option defines the pattern used to validate the email address. Valid values
   to use one of the other modes instead;
 * ``html5`` uses the same regular expression as the `HTML5 email input element`_,
   making the backend validation consistent with the one provided by browsers;
-* ``strict`` uses the `egulias/email-validator`_ library (which you must
-  install separately) for validation according to `RFC 5322`_.
+* ``strict`` validates the address according to `RFC 5322`_ using the
+  `egulias/email-validator`_ library (which is already installed when using
+  :doc:`Symfony Mailer </mailer>`; otherwise, you must install it separately).
 
 .. tip::
 
     The possible values of this option are also defined as PHP constants of
     :class:`Symfony\\Component\\Validator\\Constraints\\Email`
     (e.g. ``Email::VALIDATION_MODE_STRICT``).
 
+
 The default value used by this option is set in the
 :ref:`framework.validation.email_validation_mode <reference-validation-email_validation_mode>`
 configuration option.