title: Rider does not seem to recognize Unity project
body: <p>I have used Rider in the past on Unity projects, there was a button to start Unity Play mode from the IDE, and attach the debugger. I am using 2019.2 version of Unity and latest of Rider right now.</p>
  
  <p>I should have some icons like in the documentation here <a href="https://www.jetbrains.com/help/rider/Unity.html#" rel="nofollow noreferrer">https://www.jetbrains.com/help/rider/Unity.html#</a>.</p>
  
  <p>Nothing show up, and the best I get, is Rider proposing to add a custom configuration... Rider is correctly set as the IDE for Unity in Unity preferences. I do not understand what is going on.</p>
  
  <p><a href="https://i.stack.imgur.com/tXgrx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tXgrx.png" alt="IDE bar with missing Unity play button"></a></p>