Add more information in the Error Type.

[BennyPLS]

I think the current implementation, which includes only a message and it's the responsibility of the rule, is a little cumbersome. If I want a different error message, I need to create a custom rule. If this applies to all the rules, I believe it's worth considering programmatic access to the validation type and constraint info that failed or the constraints (Like in the param data in the Validator Crate) or the option to override the error message. I expect comments on this or even if it’s relatively easy to implement with the current state of this library or even if it's the plan.

Thanks for your time.

[jprochazk]

Please search through issues before opening new ones:

• Serialize constraints #3
• Custom error messages and localization #7
• Support custom error codes #105