title: Xcode 8 says "Do you want to add a stub?" How do I answer?
body: <p>In Xcode 8, if you declare that a class (or struct) conforms to a protocol, but haven't implemented the required methods (functions?) Xcode will give this message "Type '<code>ClassName</code>' does not conform to protocol '<code>ProtocolName</code>'" which is true.</p>
  
  <p>If you open the error by clicking the disclosure triangle, you will see a number of items with grey exclamation mark icons. Each item says "Protocol requires function ... do you want to add a stub?" I do want to add a stub! How do I tell it to add a stub for me?</p>