Keyboard input in the console still isn't quite as flexible as it is in
the video window. Ctrl+<letter> and Ctrl+LEFT/RIGHT work, but
Ctrl+Alt+<letter> and Ctrl+<number> do not. Also, in the new Windows 10
console, a bunch of Ctrl keystrokes including Ctrl+UP/DOWN are handled
by the console window and not passed to the application.
Unlike in w32_common.c, we can't really translate keyboaard input
ourselves because the keyboard layout of the console window (in
conhost.exe) doesn't necessarily match the keyboard layout of mpv's
console input thread, however, using ToUnicode as a fallback when the
console doesn't return a unicode value could be a possible future
improvement.
Fixes#3625