Add a virtual keyboard for function keys on mobile

[curiousdannii]

On mobile you can't enter function keys, arrow keys, Esc, etc on the phone's virtual keyboard. We could add a button (just above the virtual keyboard?) that would bring up a little fake keyboard just with these function keys

[dfabulich]

What games would use/require these keys?

For command history accessed via up arrow, other mobile interpreters use a "book button". curiousdannii/parchment#103

[curiousdannii]

I'm not certain there are any, the standard menu libraries all allow letter keys to substitute for arrows etc. But I'm sure there's something out there that needs non-letter keys.