it.defaultMessage is probably not the best example

using it.defaultMessage with a custom validator produces a message like:

Property [{0}] of class [{1}] with value [{2}] does not pass custom validation

Better would to be g:message which actually resolves the code:

<g:message error="${it}"/>
Merge pull request #203 from keeth/master

GRAILS-11309 hasErrors documentation: it.defaultMessage is probably not the best example