languages/html: remove null_ls usage

Remove usage of null_ls and replace it with new standards.

modules/plugins/languages/html.nix

@@ -39,18 +39,9 @@
   defaultDiagnosticsProvider = ["htmlhint"];
   diagnosticsProviders = {
     htmlhint = {
-      package = pkgs.htmlhint;
-      nullConfig = pkg: ''
-        table.insert(
-          ls_sources,
-          null_ls.builtins.diagnostics.htmlhint.with({
-            command = "${pkg}/bin/htmlhint"
-          })
-        )
-      '';
+      config.cmd = getExe pkgs.htmlhint;
     };
   };
-
 in {
   options.vim.languages.html = {
     enable = mkEnableOption "HTML language support";
@@ -140,9 +131,9 @@ in {
         enable = true;
         linters_by_ft.html = cfg.extraDiagnostics.types;
         linters = mkMerge (map (name: {
-          ${name}.cmd = getExe diagnosticsProviders.${name}.package;
-        })
-        cfg.extraDiagnostics.types);
+            ${name} = diagnosticsProviders.${name}.config;
+          })
+          cfg.extraDiagnostics.types);
       };
     })
   ]);