feat(markdown): configure conform for markdown files (#2308)

lua/lazyvim/plugins/extras/lang/markdown.lua

@@ -5,6 +5,15 @@ return {
       root = "README.md",
     })
   end,
+  {
+    "stevearc/conform.nvim",
+    optional = true,
+    opts = {
+      formatters_by_ft = {
+        markdown = { { "prettierd", "prettier" }, "markdownlint", "markdown-toc" },
+      },
+    },
+  },
   {
     "nvim-treesitter/nvim-treesitter",
     opts = function(_, opts)