add markdown preview

lua/custom/plugins/markdown_preview.lua

@@ -0,0 +1,11 @@
+-- if does not work, go manually in the folder .local/share/nvim/site/pack/packer/start/markdown-preview.nvim/app and run yarn install
+
+return {
+	"iamcco/markdown-preview.nvim",
+	run = "cd app && yarn install",
+	setup = function()
+		vim.g.mkdp_filetypes = {
+			"markdown" }
+	end,
+	ft = { "markdown" }
+}