Use RECIPROCAL macro (not _RECIP) (#16530)

Marlin/src/gcode/motion/G2_G3.cpp

   const feedRate_t scaled_fr_mm_s = MMS_SCALED(feedrate_mm_s);
 
   #ifdef ARC_SEGMENTS_PER_SEC
-    float seg_length = scaled_fr_mm_s * _RECIP(ARC_SEGMENTS_PER_SEC);
+    float seg_length = scaled_fr_mm_s * RECIPROCAL(ARC_SEGMENTS_PER_SEC);
     NOLESS(seg_length, MM_PER_ARC_SEGMENT);
   #else
     constexpr float seg_length = MM_PER_ARC_SEGMENT;