Improved Snap On Guide for "|Robert|'s Alternative UM2 Feeder V2"

This is an updated version of the snap on guide for [|Robert|'s Alternative UM2 Feeder V2](https://www.youmagine.com/designs/alternative-um2-feeder-version-two).
I created it after I tried to use this feeder for 1.75mm filament and found that it needs some additional guidance under the extruder motor.

While printing test prints with the new feeder and 2.85mm filament I also had some noise coming from the feeder which has its cause by the filament not really centered on the pressure bearing.