title: How to add static string to trusted ng-src?
body: <p>How can I achieve the following?</p>
  
  <pre><code>&lt;iframe ng-src="{{url | trusted}} + '?staticparam=test'"...&gt;
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>Error: $interpolate:noconcat
  Multiple Expressions
  </code></pre>