TERM FUNC key sends a non-standard E0 12 E0 00(Make) and E0 F0 00 E0 F0 12(Break).
Therefore, we must no longer check for 0 codes in the CS2_E0 and CS2_E0_F0 states.
The "Term Func" key is mapped to "Volume Down" by default, since that matches the
keyboard geometry.
The PS/2 controller code for Unicomp's current generation PS/2 keyboard
sends the wrong scancodes when Ctrl + Pause (which should be Break) is
pressed.
Instead of it sending the Break sequence...
E0 7E E0 F0 7E
... representing a press of Scroll Lock, which is Break because Ctrl is
being pressed, it instead sends...
E0 77
... representing a press of Num Lock, which is just the old way of
getting Pause.
Since the E0 77 coming from the controller is not a normal sequence,
this workaround does not interfere with Ctrl + Num Lock, which still
Pauses as it should.
* Add support for the DEC layout Televideo Linear Space Invader keyboards to ibmpc_usb.
See this thread for which keyboards I am referring to:
https://deskthority.net/viewtopic.php?f=2&t=25763
(Many of these keyboards are completely unbranded on the outside, and only the
PCB reads "TELEVIDEO ANSI Scan")
* Add kp comma
* Changing mapping of backspace keys, as discussed in PR review
