docs: add axis type to [AXIS_<letter>] Section

Author: phillc54

docs/src/config/ini-config.adoc

@@ -884,6 +884,11 @@ LinuxCNC will not know your joint travel limits when using `NO_FORCE_HOMING = 1`
 
 The _<letter>_ specifies one of: X Y Z A B C U V W
 
+* `TYPE = LINEAR` - The type of this axis, either `LINEAR` or `ANGULAR`.
+  Required if this axis is not a default axis type.
+  The default axis types are X,Y,Z,U,V,W = LINEAR and A,B,C = ANGULAR.
+  This setting is effective with the AXIS GUI but note that other
+  GUI's may handle things differently.
 * `MAX_VELOCITY = 1.2` - Maximum velocity for this axis in <<sub:ini:sec:traj,machine units>> per second.
 * `MAX_ACCELERATION = 20.0` - Maximum acceleration for this axis in machine units per second squared.
 * `MIN_LIMIT = -1000` - (((MIN LIMIT))) The minimum limit (soft limit) for axis motion, in machine units.

docs/src/gui/axis.adoc

@@ -34,7 +34,8 @@ When AXIS starts, a window like the one in the figure
 === INI settings
 
 For more information on INI file settings that can change how AXIS
-works see the <<sub:ini:sec:display,Display Section>> of the INI
+works see the <<sub:ini:sec:display,Display Section>> and the
+<<sub:ini:sec:axis-letter,Axis Section>> of the INI
 Configuration Chapter.
 
 * 'CYCLE_TIME' - Adjust the response rate of the GUI in