Mention luacheck's built-in Luanti support

[mark-wiemer]

          worth denoting its built in support for minetest/luanti or naw?

Originally posted by @wsor4035 in #203 (comment)

[appgurueu]

Certainly worth mentioning IMO.

Doesn't have to be much, just note that there is a builtin luanti "standard" ¹, how to use it in .luacheckrc, that it's pretty comprehensive but may at times lag behind (in which case: just add the extra APIs you're using manually to .luacheckrc), and that it generally tries to target the newest Luanti version (and maybe where they can find the source, in case they explicitly want to target an older version or want to contribute to bring it up to date with a new Luanti version).

If modders don't know this, they will probably do lazier configs which give them worse linting (e.g. no error for core.frobnication because core was just declared an opaque global), or they'd end up unnecessarily redoing the work which went into the standard themselves if they were to do it properly.

Footnotes

1. The term Luacheck uses for out-of-the box configs for certain Lua environments ↩