Add INI comments for Chunithm IO config

dist/chuni/segatools.ini

@@ -28,3 +28,39 @@ subnet=192.168.100.0
 windowed=1
 ; Add a frame to the game window if running windowed.
 framed=1
+
+; -----------------------------------------------------------------------------
+; Input settings
+; -----------------------------------------------------------------------------
+
+; Keyboard bindings are specified as hexadecimal (prefixed with 0x) or decimal
+; (not prefixed with 0x) virtual-key codes, a list of which can be found here:
+;
+; https://docs.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes
+;
+; This is, admittedly, not the most user-friendly configuration method in the
+; world. An improved solution will be provided later.
+
+[io3]
+; Test button virtual-key code. Default is the 1 key.
+test=0x31
+; Service button virtual-key code. Default is the 2 key.
+service=0x32
+; Keyboard button to increment coin counter. Default is the 3 key.
+coin=0x33
+
+; Key bindings for each of the 32 touch cells. The default key map, depicted
+; in left-to-right order, is as follows:
+;
+;                   SSSSDDDDFFFFGGGGHHHHJJJJKKKKLLLL
+;
+; Touch cells are numbered FROM RIGHT TO LEFT! starting from 1. This is in
+; order to match the numbering used in the operator menu and service manual.
+;
+; Uncomment and complete the following sequence of settings to configure a
+; custom high-precision touch strip controller if you have one.
+[slider]
+;cell32=0x53
+;cell31=0x53
+;cell30=0x53
+; ... etc ...