Voron Trident Z Carriage for MGN12C Linear Rails

I'm reusing old MGN12C rails for Z axis instead of MGN9H, Keemo already changed original models, but it's for MGN12H. Holes are spaced 15mm instead of 20mm on C carriages so I've added extra holes for those.

Use "[a]_z_carriage_left" and “[a]_z_carriage_right” from original remade models. As with original remade models, MGN12C carriages are wider than extrusions so use thick tape 4-5mm for your side panels.

Added holes for MGN12C rails (15mm vs 20mm)