DiiiCooler snap-in shim

Remix of DiiiCooler Shim for Di3 v2.1 by @grantisimo that allows insertion/removal without needing to fully remove the DiiiCooler. This allows easy testing of various shim heights and is much easier to install.

Simply loosen the two screws holding the DiiiCooler in place, place the hooked end around one screw, snap the other end onto the remaining screw, and tighten the screws back.

Note that the nozzle height on the Di3 / Di3+ is adjustable with a set screw, but it seems (at least on my unit) that for a proper cooler height, the heater block would need to be touching the mounting bracket / heatsink, with little to no heat break in between. I used a combination of adjusting the set screw (as far as I was comfortable with) and a 1.5mm shim to bring the height of the cooler to ~2mm from the tip of the nozzle. 40% fan speed is about perfect for PLA on the Di3+ with this setup; more cooling seems to affect adhesion between layers.

@Pawpawpaw85 (the creator of the DiiiCooler) st