Bear Exxa Phaetus or Triangle Labs Dragon Hotend Rigid no-turn Cover

This is a remix of the Bear Exxa extruder cover that adds a small peg that prevents the Dragon hotend from turning.

This is achieved by a the addition of a small peg that locks down into the structure of the dragon hotend and holds it rigid, allowing one hand nozzle changes with the dragon.

Update v1.1. increased compatibility with high flow version of the Dragon.