chore: format everything

This implicates a change from nixpkgs-fmt to nixfmt. Nixfmt will become
the new standard on nix formatting, sanctioned by the nixpkgs. To verify
that these changes are purely in whitespace, but not semantic:

git diff --ignore-all-space -w HEAD^!

That will only show newline changes, make the diffing somewhat easier.

Signed-off-by: wucke13 <wucke13+github@gmail.com>

treefmt.nix

@@ -17,9 +17,7 @@
       "*.yaml"
       "*.yml"
     ];
-    excludes = [
-      "supply-chain/*"
-    ];
+    excludes = [ "supply-chain/*" ];
     settings = {
       plugins = [
         "${pkgs.nodePackages.prettier-plugin-toml}/lib/node_modules/prettier-plugin-toml/lib/index.js"