Update to output data to be formatted in line with bignum v0.4.0.

The data that's generated for the `noir-bignum/fields/` dir comes from this repo. But with v0.4.0, this repo doesn't format things correctly. Data for v0.4.0 was actually updated manually, but we should update this repo to do it for us.

The bug here (https://github.com/noir-lang/noir-bignum/issues/49) can be resolved through this issue.