Update `SDL_scancode.h` which is used by `gen_keys.py` to generate the list of keys enum (`keys.h`) and the list of key names (`keynames.h`) and regenerate the lists.
This adds support for 6 uncommonly used keys (audiorewind, audiofastforward, softleft, softright, call, endcall).
Instead of considering diagonal hat inputs (e.g. up-left) as separate keys, consider them as inputs for both cardinal directions (e.g. up and left) at the same time.
This improves input with gamecontrollers that map the D-Pad to a joystick hat, as it was impossible with the previous handling to move with hat-left/right and jump with hat-up at the same time.
This means that diagonal hat buttons can no longer be used in binds, because they are no longer considered distinct buttons. It's unlikely that they would ever be useful in this game, as real joystick POV hats would not be used anyway.
Closes#6120.