title: Facebook Messenger not showing up with UIActivityViewController
body: <p>I am using UIActivityViewController in my app to provide options for users to share some text. <a href="https://i.stack.imgur.com/OnlfY.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OnlfY.jpg" alt="enter image description here"></a></p>
  
  <p>Apps like facebook, twitter, whatsapp once installed they automatically show up as options with UIActivityViewController, but not Facebook Messenger. </p>
  
  <p>Any special set up I need to do with Messenger? I am using objective c.</p>