feat: check malformed domain names

src/Exception/MalformedDomainException.php

@@ -6,6 +6,6 @@ class MalformedDomainException extends \Exception
 {
     public static function fromDomain(string $ldhName): self
     {
-        return new self("Domain name ($ldhName) must contain at least one dot");
+        return new self("Malformed domain name ($ldhName)");
     }
 }