packageDefinitions.packagename = {}:{ extra } and toLua implementation improvements

[BirdeeHub]

having everyone put all the values in categories and use the category fetcher for values is probably confusing.

It still works the same way, I just added an optional extra set to packageDefinitions named extra.

categoryDefinitions = { pkgs, settings, categories, extra, name, ... }@pkgDef: {
};
packageDefinitions = {
  packagename = { pkgs, ... }: {
    settings = {};
    categories = {};
    extra = {};
  };
};

Like the other tables, you can use nixCats.extra("path.to.val") as an alias for fetching with vim.tbl_get to protect against nil table access errors, which is different from how the main nixCats('path.to.cat') works in that, if it does not find the value, it will always return nil, rather than returning an indicator of whether it was enabled or not. You can also use :NixCats extra to view the table

utils.mkLuaInline has been renamed to utils.n2l.types.inline-safe.mk

Extra utils.n2l functions added documented at :help nixCats.flake.outputs.utils.n2l