having two classes `Failure` and `WrappingFailure` adds confusion and stops reusability

[smarie]

• one cannot reuse the same exception type easily in a custom validation function and in a failure raiser created using the simple syntax
• it is hard enough to find a name that does not pollute the final error message too much, lets not have two.

[smarie]

We could instead propose a single Invalid exception class ? Or maybe two InvalidValue / InvalidType inheriting a common ValidationFailure type ?