Common pattern for Neovim on Nix files to put language declarations as comments

[blackxored]

There's AFAIK this common pattern when you use Neovim with Nix files containing embedded strings to prefix the string with the language to get syntax highlighting of the embedded language, an example from my config:

      callback = lib.generators.mkLuaInline /* lua */ ''
        function(args)
      '';

I would prefer if alejandra didn't touch this, but here's what I get instead:

      callback =
        lib.generators.mkLuaInline
        /*
        lua
        */
        ''
          function(args)
        '';

Aside from my own suggested formatting (as I wrote it) I would not mind much if it just formatted like this (which might be easier to implement?):

      callback =
        lib.generators.mkLuaInline /* lua */
        ''
          function(args)
        '';

but I would definitely prefer the first option.

I have provided a very simple test case for the kind soul that will (hopefully) work on this:

0001-test-add-nix-language-idiom-on-embedded-strings.patch