pkg(nixvim): Remove all lang configuration to single file

pkgs/nixvim/lang/json.nix

@@ -0,0 +1,30 @@
+{
+  lib,
+  pkgs,
+  ...
+}: {
+  youthlic.plugins.conform-nvim.settings = {
+    formatters_by_ft.json = {
+      __unkeyed-1 = "deno_fmt";
+    };
+    formatters.deno_fmt = {
+      __raw =
+        #lua
+        ''
+          function()
+            local defaultFormatter = require("conform.formatters.deno_fmt")
+            return vim.tbl_extend("force", defaultFormatter, {
+              command = function()
+                local exe = vim.fn["exepath"]("deno")
+                if exe ~= "" then
+                  return exe
+                else
+                  return "${lib.getExe pkgs.deno}"
+                end
+              end
+            })
+          end
+        '';
+    };
+  };
+}