Added M862 details

Firmware/Marlin_main.cpp

@@ -7285,6 +7285,24 @@ Sigma_Exit:
    
     //! ### M862 - Print checking
     // ----------------------------------------------
+    /*!     
+        Checks the parameters of the printer and gcode and performs compatibility check
+
+          - M862.1 [ P<nozzle_diameter> | Q ]
+
+          - M862.2 [ P<model_code> | Q ]
+
+          - M862.3 [ P<model_name> | Q ]
+
+          - M862.4 [ P<fw_version> | Q]
+
+          - M862.5 [ P<gcode_level> | Q]
+
+
+          When run with P<> argument, the check is performed against the input value.
+          When run with Q argument, the current value is shown.
+
+    */
     case 862: // M862: print checking
           float nDummy;
           uint8_t nCommand;