add null-ls formatting

lua/custom/plugins/init.lua

@@ -8,4 +8,8 @@ return {
 	dependencies = {
 		"nvim-lua/plenary.nvim",
 	},
+	"jose-elias-alvarez/null-ls.nvim",
+	ft = { "python" },
+
+	"jay-babu/mason-null-ls.nvim",
 }

lua/custom/plugins/null-ls.lua

@@ -0,0 +1,14 @@
+null_ls = require("null-ls")
+
+return {
+
+	null_ls.setup({
+		sources = {
+			null_ls.builtins.formatting.black,
+		},
+	}),
+
+	require("mason-null-ls").setup({
+		ensure_installed = { "black" }
+	}),
+}