doc: update configuration docs on custom plugins

docs/manual/configuring/custom-plugins/non-lazy-method.md

@@ -0,0 +1,26 @@
+# Non-lazy Method {#sec-non-lazy-method}
+
+As of version **0.5**, we have a more extensive API for configuring plugins,
+under `vim.extraPlugins`. Instead of using DAGs exposed by the library, you may
+use the extra plugin module as follows:
+
+```nix
+{
+  config.vim.extraPlugins = with pkgs.vimPlugins; {
+    aerial = {
+      package = aerial-nvim;
+      setup = ''
+        require('aerial').setup {
+          -- some lua configuration here
+        }
+      '';
+    };
+
+    harpoon = {
+      package = harpoon;
+      setup = "require('harpoon').setup {}";
+      after = ["aerial"];
+    };
+  };
+}
+```