Fix for VS Code

pick works within VS Code on Windows for me if I change the KEYS_UP and KEYS_DOWN to

```
VS_CODE_KEY_UP = 456
VS_CODE_KEY_DOWN = 450
KEYS_UP = (curses.KEY_UP, ord("k"), VS_CODE_KEY_DOWN)
KEYS_DOWN = (curses.KEY_DOWN, ord("j"), VS_CODE_KEY_UP)
```

Could we get an option to add keycodes?