Symfony version(s) affected: any?

Description
As warned in the comment to checkdnsrr() docs, one should pass a fully qualified domain name to get correct results, i.e. symfony.com. instead of symfony.com

99.9% of the time users do not put a dot at the end of their email which leads to incorrect checks.

Possible Solution without breaking BC

1. Add a config value framework.validation.make_host_absolute = null (like framework.validation.make_host_absolute). If not set explicitly to true or false a deprecation is shown: Not setting a value explicitly is deprecated. Will be true by default since 5.0.
2. Add EmailValidator::__construct(..., ?bool $makeHostAbsolute = null) with same BC logic.
3. Add @Email::?bool $makeHostAbsolute = null to be able to override validator's default value when needed.
4. if ($makeHostAbsolute && '.' !== mb_substr($email, -1)) { $email .= '.'; }

Ready to work on the PR.