* ^[O is Shift-Alt-O, not Alt-O. Alt-O is ^[o
* '[' is not a valid virtualkey. It's typically VK_OEM_4 on a US
keyboard, but it needs to be looked up dynamically.
* The unicodeChar fields should be 'O' and '[', not NUL.
* Add a --showkey argument to the unix adapter.
My Ubuntu machine has a nice showkey -a utility that dumps keys, but I
can't find something similar for Cygwin/MSYS. It's a very useful tool
for debugging UNIX terminal interoperability, so add it to the unix
adapter.
* Add WINPTY_DEBUG=input to log input bytes and console key events.
