chore: remove jsonnet and add luafmt

Signed-off-by: jolheiser <john.olheiser@gmail.com>

apps/helix.nix

@@ -151,20 +151,19 @@
     };
     languages = {
       language = [
-        {
-          name = "jsonnet";
-          auto-format = true;
-          formatter = {
-            command = "jsonnetfmt";
-            args = ["-"];
-          };
-        }
         {
           name = "go";
           formatter = {
             command = "gofumpt";
           };
         }
+        {
+          name = "lua";
+          formatter = {
+            command = "luafmt";
+            args = ["--stdin"];
+          };
+        }
         {
           name = "python";
           auto-format = true;