Update unwrap docs

[msosnicki]

Description of changes:
The documentation of unwrap currently mentions only ERROR, but in the implementation, isBroken with following implementation is used:

    public boolean isBroken() {
        for (ValidationEvent event : events) {
            if (event.getSeverity() == Severity.ERROR || event.getSeverity() == Severity.DANGER) {
                return true;
            }
        }
        return false;
    }

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[sugmanue]

@msosnicki thank you for you contribution.