Add a lot more keycode defines

[dylwhich]

Adds a whole bunch of defines for all the rest of the keycodes. All the existing ones have the same value and none were removed.

Windows keycodes came from here: https://learn.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes

X11 ones from here: https://www.cl.cam.ac.uk/~mgk25/ucs/keysymdef.h

And the WASM keycodes I got myself from the keyCode attribute of JS events.

[dylwhich]

I'm not sure if there's a plan to do anything about KeyboardEvent.keyCode being deprecated since that's the key value that's expected. The new way to handle keys is supposed to be either using .key or .code which don't actually provide numeric codes, so there would probably need to be some translation to make sure the codes are consistent. But the keys are documented pretty well here: https://developer.mozilla.org/en-US/docs/Web/API/UI_Events/Keyboard_event_code_values

[cnlohr]

the right way forward here has been under debate. But, this is an incremental change to the status quo. So, I'd like to accept this PR unless you see some other issue with it.

[dylwhich]

the right way forward here has been under debate. But, this is an incremental change to the status quo. So, I'd like to accept this PR unless you see some other issue with it.

Okay! Yeah, in that case these changes are ready