Ensure Code can represent the USB standard

[madsmtm]

keyboard-types is based on the W3C specification, but dependencies use it in a desktop context too, and thus we extend Code with extra variants to allow for these use-cases too (currently the Chromium key codes).

Another place where it could make sense to extend support for would be the USB usage page standard. The spec is available here, see specifically the Keyboard/Keypad Page 0x07 and the Consumer Page 0x0C.

This would allow representing all the scancode events that the SDL emits.