add nix lsp and formatter

lua/config/lsp/nix.lua

@@ -0,0 +1,59 @@
+local ok, lspconfig, conform, lint = pcall(function()
+  return
+      require("lspconfig"),
+      require("conform"),
+      require("lint")
+end)
+
+if not ok then
+  return
+end
+
+lspconfig.nixd.setup({
+  -- capabilities = cmp_nvim_lsp.default_capabilities()
+  capabilities = require("config/lsp/lsp-capabilities"),
+  on_attach = require("config/lsp/lsp-attach"),
+  settings = {
+    nixd = {
+      nixpkgs = {
+        expr = "import <nixpkgs> { }",
+      },
+      -- formatting = {
+      --   command = { "nixfmt" },
+      -- },
+    },
+  },
+})
+
+-- conform.setup({
+--   formatters_by_ft = {
+--     nix = { "nixfmt" },
+--   },
+--   format_on_save = {
+--     async = false,
+--     timeout_ms = 500,
+--     lsp_format = "fallback",
+--   },
+-- })
+--
+-- vim.keymap.set({ "n", "v" }, "<leader>lf", function()
+--   conform.format({
+--     async = false,
+--     timeout_ms = 500,
+--     lsp_format = "fallback",
+--   })
+-- end, { desc = "Format" })
+
+-- lint.linters_by_ft = {
+--   lua = { "luacheck" },
+-- }
+--
+-- vim.api.nvim_create_autocmd({ "BufEnter", "BufWritePost", "InsertLeave" }, {
+--   callback = function()
+--     lint.try_lint()
+--   end,
+-- })
+--
+-- vim.keymap.set("n", "<leader>ll", function()
+--   lint.try_lint()
+-- end, { desc = "Lint" })