Added circle pattern for nozzle cleaning feature

Marlin/Configuration.h

@@ -96,7 +96,7 @@
 //
 // Marlin now allow you to have a vendor boot image to be displayed on machine
 // start. When SHOW_CUSTOM_BOOTSCREEN is defined Marlin will first show your
-// custom boot image and them the default Marlin boot image is shown.
+// custom boot image and then the default Marlin boot image is shown.
 //
 // We suggest for you to take advantage of this new feature and keep the Marlin
 // boot image unmodified. For an example have a look at the bq Hephestos 2
@@ -1000,6 +1000,9 @@
 //                       |________|_________|_________|
 //                           T1        T2        T3
 //
+//   P2: This starts a circular pattern with circle with middle in
+//       NOZZLE_CLEAN_CIRCLE_MIDDLE radius of R and stroke count of S.
+//       Before starting the circle nozzle goes to NOZZLE_CLEAN_START_POINT.
 //
 // Caveats: End point Z should use the same value as Start point Z.
 //
@@ -1011,7 +1014,7 @@
 #if ENABLED(NOZZLE_CLEAN_FEATURE)
   // Default number of pattern repetitions
   #define NOZZLE_CLEAN_STROKES  12
-  
+
   // Default number of triangles
   #define NOZZLE_CLEAN_TRIANGLES  3
 
@@ -1019,6 +1022,13 @@
   #define NOZZLE_CLEAN_START_POINT { 30, 30, (Z_MIN_POS + 1)}
   #define NOZZLE_CLEAN_END_POINT   {100, 60, (Z_MIN_POS + 1)}
 
+  // Circular pattern radius
+  #define NOZZLE_CLEAN_CIRCLE_RADIUS 6.5
+  // Circular pattern circle fragments number
+  #define NOZZLE_CLEAN_CIRCLE_FN 10
+  // Middle point of circle
+  #define NOZZLE_CLEAN_CIRCLE_MIDDLE NOZZLE_CLEAN_START_POINT
+
   // Moves the nozzle to the initial position
   #define NOZZLE_CLEAN_GOBACK
 #endif