fix output extruder type for supports

src/kiri-mode/fdm/prepare.js

@@ -805,7 +805,7 @@ function slicePrintPath(print, slice, startPoint, offset, output, opt = {}) {
     let preout = [],
         process = opt.params || settings.process,
         originCenter = device.originCenter || bedRound,
-        extruder = slice.extruder || 0,
+        extruder = parseInt(slice.extruder || 0),
         nozzleSize = process.sliceLineWidth || device.extruders[extruder].extNozzle,
         firstLayer = (opt.first || false) && !opt.support,
         thinWall = nozzleSize * (opt.thinWall || 1.75),