is this make sence (or not) if some exception messages have no dot at the end ?
according to this pull request #11215 all Exception message should have a dot at the end.
for example this Exception https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Validator/Constraints/EmailValidator.php#L64 or this https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Validator/Constraints/File.php#L66.