Change signature of linearization rules.
Give the rule the nonzero tangent pattern up-front. This is needed to make a
linearization rule for pjit_p. Also make the rules return the nonzero tangents
out, an explicit residual, and a closed tangent function. Add a rule for sin_p
to test it out. We still need to figure out how to avoid having to precompute
`cos(x)`. I think we need to update our backward pass code.
