Correct the comment about M206

Marlin/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/configurator/config/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/Felix/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/Felix/Configuration_DUAL.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/Hephestos/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/K8200/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/SCARA/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/WITBOX/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/delta/generic/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/delta/kossel_mini/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/makibox/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles

Marlin/example_configurations/tvrrug/Round2/Configuration.h

 // Servo Endstops
 //
 // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes.
-// Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500.
+// Use M851 to set the z-probe vertical offset from the nozzle. Store that setting with M500.
 //
 //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles