[Validator] Clarify UUID validator behavior

Author: ro0NL

Constraints/UuidValidator.php

@@ -18,13 +18,19 @@
 use Symfony\Component\Validator\Exception\UnexpectedTypeException;
 
 /**
- * Validates whether the value is a valid UUID per RFC 4122.
+ * Validates whether the value is a valid UUID (also known as GUID).
+ *
+ * Strict validation will allow a UUID as specified per RFC 4122.
+ * Loose validation will allow any type of UUID.
+ *
+ * For better compatibility, both loose and strict, you should consider using a specialized UUID library like "ramsey/uuid" instead.
  *
  * @author Colin O'Dell <colinodell@gmail.com>
  * @author Bernhard Schussek <bschussek@gmail.com>
  *
  * @see http://tools.ietf.org/html/rfc4122
  * @see https://en.wikipedia.org/wiki/Universally_unique_identifier
+ * @see https://github.com/ramsey/uuid
  */
 class UuidValidator extends ConstraintValidator
 {