Document `tree_viz` changes about pytreeclass HOT 3 CLOSED

Seems like jax is moving to integrate key path into tree_util functions.
This will probably simplify the current approach in tree_pprint.py and tree_viz_util.py that uses jax registry handler to fetch their leaves and tries to match with their names based on their data structure.

google/jax#14710

the future API will be under
register_pytree_with_keys,
egister_pytree_with_keys_class,
tree_map_with_path,
tree_flatten_with_path,

https://github.com/google/jax/blob/ad8c39ad7ca35de3fbd2fce361e7a2f4861ecbd7/jax/_src/tree_util.py

from pytreeclass.

#39 Implements a Jax-styled registry to unify the backend for tree viz and indexing.

from pytreeclass.

Also, once we are on jax>=0.4.6 , try to fetch keys from key path registry if exists, instead of automatic naming "leaf_i"

from pytreeclass.