plugins/cmp: add description to elevate autoEnableSource info

plugins/completion/cmp/default.nix

@@ -16,6 +16,46 @@ helpers.neovim-plugin.mkNeovimPlugin config {
 
   maintainers = [ maintainers.GaetanLepage ];
 
+  description = ''
+    ### Completion Source Installation
+
+    If `plugins.cmp.autoEnableSources` is `true` Nixivm will automatically enable the corresponding source
+    plugins. This is the default behavior, but will work only when this option is set to a list.
+
+    If you use a raw lua string or set `plugins.cmp.autoEnableSources` to `false`, you will need to explicitly enable the relevant source plugins in
+    your nixvim configuration.
+
+    #### With auto-enabled sources
+    ```nix
+    plugins.cmp = {
+      autoEnableSources = true;
+      settings.sources = [
+        { name = "nvim_lsp"; }
+        { name = "path"; }
+        { name = "buffer"; }
+      ];
+    };
+    ```
+
+    #### Without auto-enabled sources
+    ```nix
+    plugins = {
+      cmp = {
+        autoEnableSources = false;
+        settings.sources = [
+          { name = "nvim_lsp"; }
+          { name = "path"; }
+          { name = "buffer"; }
+        ];
+      };
+      cmp-nvim-lsp.enable = true;
+      cmp-path.enable = true;
+      cmp-buffer.enable = true;
+    };
+
+    ```
+  '';
+
   imports = [
     # Introduced on 2024 February 21
     # TODO: remove ~June 2024