title: knockout-validation custom error message for pattern validator using html5 syntax
body: <p>I'm using the HTML5 syntax of knockout-validation to validate that the user has entered a valid number like this:</p>
  
  <pre><code>&lt;input type="text" data-bind="value: Lots" pattern="^\d*\.?\d*$" /&gt;
  </code></pre>
  
  <p>It works great, but the error message just says <code>'Invalid!'.</code><br>
  Is there a way to customize the validation message that appears when using the HTML% syntax?</p>