config: The delta_calibrate bed radius uses nozzle coordinates

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-delta.cfg

@@ -113,17 +113,19 @@ delta_radius: 174.75
 # angles.
 [delta_calibrate]
 radius: 50
-#   Radius (in mm) of the area that may be probed. This is typically
-#   the size of the printer bed. This parameter must be provided.
+#   Radius (in mm) of the area that may be probed. This is the radius
+#   of nozzle coordinates to be probed; if using an automatic probe
+#   with an XY offset then choose a radius small enough so that the
+#   probe always fits over the bed. This parameter must be provided.
 #speed: 50
-#   The speed (in mm/s) of non-probing moves during the
-#   calibration. The default is 50.
+#   The speed (in mm/s) of non-probing moves during the calibration.
+#   The default is 50.
 #horizontal_move_z: 5
 #   The height (in mm) that the head should be commanded to move to
 #   just prior to starting a probe operation. The default is 5.
 #samples: 1
-#   The number of times to probe each point.  The probed z-values
-#   will be averaged.  The default is to probe 1 time.
+#   The number of times to probe each point.  The probed z-values will
+#   be averaged. The default is to probe 1 time.
 #sample_retract_dist: 2.0
-#   The distance (in mm) to retract between each sample if
-#   sampling more than once.  Default is 2mm.
+#   The distance (in mm) to retract between each sample if sampling
+#   more than once. The default is 2mm.