Feature Request: Additional keycodes

[LiSongMWO]

For me the main use case would be to test "special" keys like VK_F21 (not a typo, see: MSDN and USB HID).

As far as I can see, these are currently not supported in:

keybd_event/keybd_windows.go

Lines 166 to 180 in 45629df

	VK_F1 = 59
	VK_F2 = 60
	VK_F3 = 61
	VK_F4 = 62
	VK_F5 = 63
	VK_F6 = 64
	VK_F7 = 65
	VK_F8 = 66
	VK_F9 = 67
	VK_F10 = 68
	VK_F11 = 87
	VK_F12 = 88
	VK_NUMLOCK = 69
	VK_SCROLLLOCK = 70

Would it be possible to add these?

[micmonay]

Hi

On Mac OS I doesn't find the keycodes. Now, The library is compatible with Linux and Windows for keys F13 at F24.

Best regard

[LiSongMWO]

Thank you!