Add Mason and Null-ls plugins for Neovim

lua/custom/plugins/mason-null-ls.lua

@@ -0,0 +1,19 @@
+return {
+  "jay-babu/mason-null-ls.nvim",
+  event = { "BufReadPre", "BufNewFile" },
+  dependencies = {
+    "williamboman/mason.nvim",
+    "jose-elias-alvarez/null-ls.nvim",
+  },
+  config = function()
+    require("mason-null-ls").setup({
+      -- list of formatters & linters for mason to install
+      ensure_installed = {
+        "prettierd", -- ts/js formatter
+        "eslint_d",  -- ts/js linter
+      },
+      -- auto-install configured formatters & linters (with null-ls)
+      automatic_installation = true,
+    })
+  end,
+}