nvim-lint: add lint after save autocmd

modules/plugins/diagnostics/nvim-lint/config.nix

@@ -3,18 +3,36 @@
   lib,
   ...
 }: let
-  inherit (lib.modules) mkIf;
+  inherit (lib.modules) mkIf mkMerge;
+  inherit (lib.generators) mkLuaInline;
   inherit (lib.nvim.dag) entryAnywhere;
   inherit (lib.nvim.lua) toLuaObject;
 
   cfg = config.vim.diagnostics.nvim-lint;
 in {
-  config = mkIf cfg.enable {
+  config = mkMerge [
+    (mkIf cfg.enable {
       vim = {
         startPlugins = ["nvim-lint"];
         pluginRC.nvim-lint = entryAnywhere ''
           require("lint").linters_by_ft = ${toLuaObject cfg.linters_by_ft}
         '';
       };
+    })
+    (mkIf cfg.lint_after_save {
+      vim = {
+        augroups = [{name = "nvf_nvim_lint";}];
+        autocmds = [
+          {
+            event = ["BufWritePost"];
+            callback = mkLuaInline ''
+              function()
+                require("lint").try_lint()
+              end
+            '';
+          }
+        ];
       };
+    })
+  ];
 }

modules/plugins/diagnostics/nvim-lint/nvim-lint.nix

@@ -21,5 +21,7 @@ in {
         accept.
       '';
     };
+
+    lint_after_save = mkEnableOption "autocmd to lint after each save" // {default = true;};
   };
 }