Configurable Corner Leveling point order (#20733)

Marlin/Configuration.h

@@ -1451,6 +1451,25 @@
     #define LEVEL_CORNERS_VERIFY_RAISED   // After adjustment triggers the probe, re-probe to verify
     //#define LEVEL_CORNERS_AUDIO_FEEDBACK
   #endif
+
+  /**
+   * Corner Leveling Order
+   *
+   * Set 2 or 4 points. When 2 points are given, the 3rd is the center of the opposite edge.
+   *
+   *  LF  Left-Front    RF  Right-Front
+   *  LB  Left-Back     RB  Right-Back
+   *
+   * Examples:
+   *
+   *      Default        {LF,RB,LB,RF}         {LF,RF}           {LB,LF}
+   *  LB --------- RB   LB --------- RB    LB --------- RB   LB --------- RB
+   *  |  4       3  |   | 3         2 |    |     <3>     |   | 1           |
+   *  |             |   |             |    |             |   |          <3>|
+   *  |  1       2  |   | 1         4 |    | 1         2 |   | 2           |
+   *  LF --------- RF   LF --------- RF    LF --------- RF   LF --------- RF
+   */
+  #define LEVEL_CORNERS_LEVELING_ORDER { LF, RF, RB, LB }
 #endif
 
 /**