More explicit junction/jerk math

Marlin/src/module/planner.cpp

         const float junction_acceleration = limit_value_by_axis_maximum(block->acceleration, junction_unit_vec),
                     sin_theta_d2 = SQRT(0.5f * (1.0f - junction_cos_theta)); // Trig half angle identity. Always positive.
 
-        vmax_junction_sqr = JUNC_SQ(junction_acceleration, sin_theta_d2);
+        vmax_junction_sqr = junction_acceleration * junction_deviation_mm * sin_theta_d2 / (1.0f - sin_theta_d2);
 
         if (block->millimeters < 1) {
           const float neg = junction_cos_theta < 0 ? -1 : 1,
                *  for (float t = 0; t <= 1; t += 0.0003f) {
                *    const float e = acos(t) / approx(t);
                *    if (isfinite(e)) {
-               *      NOMORE(min, e);
-               *      NOLESS(max, e);
+               *      if (e < min) min = e;
+               *      if (e > max) max = e;
                *    }
                *  }
                *  fprintf(stderr, "%.9gf, ", (min + max) / 2);

Marlin/src/module/planner.h

       static void autotemp_update();
     #endif
 
-    #define JUNC_SQ(N,ST) (junction_deviation_mm * (N) * (ST) / (1.0f - (ST)))
-
     #if HAS_LINEAR_E_JERK
       FORCE_INLINE static void recalculate_max_e_jerk() {
-        #define GET_MAX_E_JERK(N) SQRT(JUNC_SQ(N,SQRT(0.5)))
+        #define GET_MAX_E_JERK(N) SQRT(junction_deviation_mm * (N) * SQRT(0.5) / (1.0f - SQRT(0.5)))
         #if ENABLED(DISTINCT_E_FACTORS)
           LOOP_L_N(i, EXTRUDERS)
             max_e_jerk[i] = GET_MAX_E_JERK(settings.max_acceleration_mm_per_s2[E_AXIS_N(i)]);