homing_heaters: Turn off heaters during homing/probing (#2486)

Signed-off-by: Mike Stiemke <fandjango@gmx.de>

config/example-extras.cfg

@@ -791,6 +791,18 @@
 #   by during the check_gain_time check. It is rare to customize this
 #   value. The default is 2.
 
+# Tool to disable heaters when homing or probing an axis
+#[homing_heaters]
+#steppers:
+#   A comma separated list of steppers that should cause heaters to be
+#   disabled. The default is to disable heaters for any homing/probing
+#   move.
+#   Typical example: stepper_z
+#heaters:
+#   A comma separated list of heaters to disable during homing/probing
+#   moves. The default is to disable all heaters.
+#   Typical example: extruder, heater_bed
+
 # MAXxxxxx serial peripheral interface (SPI) temperature based
 # sensors. The following parameters are available in heater sections
 # that use one of these sensor types.