Alert users about low Z jerk values

Marlin/src/gcode/config/M200-M205.cpp

@@ -132,6 +132,12 @@ void GcodeSuite::M205() {
   if (parser.seen('B')) planner.min_segment_time_us = parser.value_ulong();
   if (parser.seen('X')) planner.max_jerk[X_AXIS] = parser.value_linear_units();
   if (parser.seen('Y')) planner.max_jerk[Y_AXIS] = parser.value_linear_units();
-  if (parser.seen('Z')) planner.max_jerk[Z_AXIS] = parser.value_linear_units();
+  if (parser.seen('Z')) {
+    planner.max_jerk[Z_AXIS] = parser.value_linear_units();
+    #if HAS_MESH
+      if (planner.max_jerk[Z_AXIS] <= 0.1)
+        SERIAL_ECHOLNPGM("WARNING! Low Z Jerk may lead to unwanted pauses.");
+    #endif
+  }
   if (parser.seen('E')) planner.max_jerk[E_AXIS] = parser.value_linear_units();
 }

Marlin/src/inc/SanityCheck.h

@@ -879,7 +879,9 @@ static_assert(X_MAX_LENGTH >= X_BED_SIZE && Y_MAX_LENGTH >= Y_BED_SIZE,
 
 #endif
 
-#if !HAS_MESH && ENABLED(G26_MESH_VALIDATION)
+#if HAS_MESH
+  static_assert(DEFAULT_ZJERK > 0.1, "Low DEFAULT_ZJERK values are incompatible with mesh-based leveling.");
+#elif ENABLED(G26_MESH_VALIDATION)
   #error "G26_MESH_VALIDATION requires MESH_BED_LEVELING, AUTO_BED_LEVELING_BILINEAR, or AUTO_BED_LEVELING_UBL."
 #endif