docs: refactor

docs/manual/hacking/additional-plugins.md

@@ -0,0 +1,33 @@
+# Adding Plugins {#sec-additional-plugins}
+
+To add a new neovim plugin, first add the source url in the inputs section of `flake.nix`
+
+```nix
+
+{
+  inputs = {
+    # ...
+    neodev-nvim = {
+      url = "github:folke/neodev.nvim";
+      flake = false;
+    };
+    # ...
+  };
+}
+```
+
+Then add the name of the plugin into the `availablePlugins` variable in `lib/types/plugins.nix`:
+
+```nix
+# ...
+availablePlugins = [
+  # ...
+  "neodev-nvim"
+];
+```
+
+You can now reference this plugin using its string name:
+
+```nix
+config.vim.startPlugins = ["neodev-nvim"];
+```