question: followup on why args in perSystem does not work

[gabyx]

This is a followup on: #302.

Hi @roberth 😀
This documentation effort is so good! It explains a lot what I missed:

There were some questions or things which still are a bit ominous to me and I could not yet decipher:

• args@{a,b, ...} and {a,b,...}@args is not the same? So the first binds to the original set, the latter only to the destructured stuff, right?

• _module is an internal option of the module system where _module.args represents all additional arguments which are passed to all module functions. Quite hard to grasp since its recursive as you describe.

• _module.args inside perSystem is not the same instance as inside top level module scope config = {...}.

• I guess I can now forward all arguments in perSystem to a function foo like this?

   {config, ...}: {
      perSystem = {...}: {  foo  config.allModuleArgs };
   }

Thanks for answering these hard questions and also updating the docs! It really helps!