[ new ] Snake! Using IR!

[gallais]

Building on top of #27

As I said on discord:

Running it should be as simple as going into examples/snake and running make && ./build/exec/snake (you may need to explicitly say NCURSES_VERSION=X make instead of make with X either 5 or 6 depending on the version of ncurses you have installed)

[mattpolzin]

I absolutely love this example.

Can you (a) merge main in now that I've merged the PR for the branch on which this was based and (b) build this example in CI a la https://github.com/mattpolzin/ncurses-idris/blob/main/.github/workflows/ci.yml#L61..L65 so future changes to the library don't break this code.

For CI, don't bother with the checks I do for the longer example at the end, just the basic build like for all the other examples.