Function validationFailure

validationFailure(...errors: string[]): ValidationResult.Failure
Function to be called and returned by validation functions to indicate invalidity.
Parameters
- ...errors: string[]
  messages indicating why the value was not valid
Returns ValidationResult.Failure
Example
```
if (value <= 0) {
    return validationFailure("value must be greater than 0", ...previousErrors);
}
```