Update example in "Adding JAX and Numba support for Ops" (#687)

* Changed example for extending JAX. * Changed example for extending JAX. * Use CumOp in the example * Delete new_jax_example.ipynb

Update example in "Adding JAX and Numba support for Ops" (#687)
ca7e8b8b · Pham Nguyen Hung · GitHub · 30b760f2 · ca7e8b8b
--- a/doc/extending/creating_a_numba_jax_op.rst
+++ b/doc/extending/creating_a_numba_jax_op.rst