Followup to meshCount patch

Marlin/src/gcode/bedlevel/abl/G29.cpp

@@ -225,7 +225,7 @@ G29_TYPE GcodeSuite::G29() {
   #if ABL_GRID
 
     #if ENABLED(PROBE_MANUALLY)
-      ABL_VAR xy_uint8_t meshCount;
+      ABL_VAR xy_int8_t meshCount;
     #endif
 
     ABL_VAR xy_float_t probe_position_lf, probe_position_rb;

Marlin/src/lcd/extensible_ui/ui_api.h

@@ -137,8 +137,7 @@ namespace ExtUI {
       bed_mesh_t& getMeshArray();
       float getMeshPoint(const xy_uint8_t &pos);
       void setMeshPoint(const xy_uint8_t &pos, const float zval);
-      void onMeshUpdate(const uint8_t xpos, const uint8_t ypos, const float zval);
+      void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval);
-      inline void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) { onMeshUpdate((uint8_t)xpos, (uint8_t)ypos, zval); }
       inline void onMeshUpdate(const xy_int8_t &pos, const float zval) { onMeshUpdate(pos.x, pos.y, zval); }
     #endif
   #endif

Marlin/src/lcd/extui_example.cpp

@@ -89,7 +89,7 @@ namespace ExtUI {
     // whether successful or not.
   }
 
-  void onMeshUpdate(const uint8_t xpos, const uint8_t ypos, const float zval) {
+  void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
     // This is called when any mesh points are updated
   }
 }