Support mouse parsing for neovim terminal

[litoj]

Neovim terminal has some misses, but my own input parser works just fine with it, so I think the problem is not on their side this time.

Disclaimer: haven't tried with normal notcurses, just used notcurses-input - if this is just specific to it, please ignore me

notcurses seems to send ^[[?1016l to receive input with pixel precission, I don't know if that is a default behaviour or an option set by notcurses-input to show its full potential, but Neovim understands only 1006 - cell-precission position reporting, which notcurses-input doesn't send as a fallback. This results in neovim printing mouse events in the default format, therefore not being parsed by notcurses-input.

Reproducible with: nvim -c ":term notcurses-input" + mouseclick