fix(markdown): add marksman to mason install

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

@@ -11,7 +11,7 @@ return {
     "williamboman/mason.nvim",
     opts = function(_, opts)
       opts.ensure_installed = opts.ensure_installed or {}
-      vim.list_extend(opts.ensure_installed, { "markdownlint" })
+      vim.list_extend(opts.ensure_installed, { "markdownlint", "marksman" })
     end,
   },
   {