v1.20.0

⚠️ Deprecations

• Connecting to existing ZMQ kernels via a connection.json file feature now fully removed #919
  • Deprecated in favor of kernel gateways

🎉 Features

• Use ctrl/cmd+click to open in editor (removes need for open in editor button) #941, #942
  
• Enable hydrogen debug output toggling without reloading atom #925, #927

📝 Documentation

• Simplify plotly - matplotlib example #916

👷 Internal Improvements

• Use mutable data structures to work better with mobx #917