add flakeModule to hopefully generate docs

modules/flake-parts.nix

@@ -1,5 +1,9 @@
 { inputs, self, ...}: {
-  config.systems = [
+  systems = [
     "x86_64-linux"
   ];
+
+  flake.flakeModules = {
+    docs-entry-point = inputs.import-tree.filterNot (inputs.nixpkgs.lib.hasInfix "flake-parts") "${self}/modules";
+  };
 }