"invalid escape sequence" warning in `BoxOSQP` docstring

[nardi]

Kind of a minor issue, but the lines

https://github.com/google/jaxopt/blob/501cc208c2493395fbe8026b963e7867397403db/jaxopt/_src/osqp.py#L333-L336

in the BoxOSQP docstring cause a DeprecationWarning: invalid escape sequence '\m'. Would changing them to

  Dual Ineq variables: :math:`\\mu, \\phi`


  ADMM computes :math:`y` at each iteration. :math:`\\mu` and :math:`\\phi` can be deduced from :math:`y`.

fix that while leaving the proper docstring in tact?

There is also another mistake in the same docstring:

https://github.com/google/jaxopt/blob/501cc208c2493395fbe8026b963e7867397403db/jaxopt/_src/osqp.py#L318

Here ``jnp.inf does not have a closing ``.