Add documentation entry for new offset/size configuration option

Author: baldurk

docs/window/settings_window.rst

@@ -100,6 +100,14 @@ Examples:
 
 * With a value of 2, ``123456789.0`` will be displayed as *1.2345E8*
 
+---------------
+
+  | :guilabel:`Offset or size fields format mode` Default: ``Auto``
+
+Any fields which are displayed in the UI that represent byte offsets or sizes can be configured to display as either decimal, hexadecimal, or automatic.
+
+In the default automatic mode the fields will be shown as decimal for small values up to a given threshold, and as hexadecimal for larger values. With this option they can be instead forced to always display as one or the other.
+
 ---------------
 
   | :guilabel:`Directory for temporary capture files` Default: ``%TEMP%``