link to nn libraries in readme
link to nn libraries in readme

Co-authored-by: Skye Wanderman-Milne <4c878c1ae364587078acae22009e8542fed717b6@google.com>
Co-authored-by: James Bradbury <02b6560c5e1f8e1f3921a749812ddc945f39e7c1@google.com>
tensorflow/probability,tensorflow/probability,google/jax,google/jax,google/jax,google/jax