title: Give RequiredAttribute a custom message
body: <p>I have a required message and I want to give it a custom message because the default one is not great.  The message must come from a resource file and is parametrized, so the message in the resource file will be something like</p>
  
  <pre><code>"The {0} field is required."
  </code></pre>
  
  <p>I need to be able to replace {0} with something I supply.  I know the default message is similar but the problem is I end up with things like </p>
  
  <pre><code>"The RequiredReason field is required."
  </code></pre>
  
  <p>when what I want is</p>
  
  <pre><code>"The required reason field is required".
  </code></pre>
  
  <p>Any idea how this can be done?</p>