Circular references use special ref links: (ref obj_0)

Now I see in readme we add special marker/reference/keyword ref. And it is redundant.

For example:

const obj = {
  "self": obj
  "other": { "1": 1, "2": 2 }
};

Self reference should be translated as (or similar):

(obj: 
  (self obj)
  (other (
     (1 1)
     (2 2)
   ))
)

to links notation

How to read links notation:

(self-reference: first-reference second-reference ...)

Implement new style in both JS and Python versions.