title: resharper extract interface grayed out
body: <p>how to create an interface off of a class using resharper?
  the option is grayed out.</p>
  
  <p>VS does have an option for refactoring the interface out of the class but resharper takes it out by default.</p>
  
  <p><img src="https://i.stack.imgur.com/4gzKV.jpg" alt="enter image description here"></p>