Remove jax.scipy.misc.
The only function in jax.scipy.misc is logsumexp, which is also available as jax.scipy.special.logsumexp.
scipy.misc.logsumexp is gone from recent scipy versions, and users found the current jax behavior where the misc name was present only if the scipy equivalent was confusing. Instead, just remove it; users should use jax.scipy.special.logsumexp instead.
