[DOC]: `thrust::stable_sort` docs are wrong

### Is this a duplicate?

- [x] I confirmed there appear to be no [duplicate issues](https://github.com/NVIDIA/cccl/issues) for this bug and that I agree to the [Code of Conduct](CODE_OF_CONDUCT.md)

### Is this for new documentation, or an update to existing docs?

Update

### Describe the incorrect/future/missing documentation

In the documentation page of overloads of `thrust::stable_sort` we are showing an example where `thrust::sort` is being used instead of `thrust::stable_sort`.

here:

https://github.com/NVIDIA/cccl/blob/deb90107357dd90ba10115dfd6cd8bf2831fce78/thrust/thrust/sort.h#L349
https://github.com/NVIDIA/cccl/blob/deb90107357dd90ba10115dfd6cd8bf2831fce78/thrust/thrust/sort.h#L398

While at it, I think I'll take the liberty to also change the examples as to showcase the stability too (e.g. sort pairs `(0,'x), (2,'y'), (2,'z')` so that elements are identifiable).

### If this is a correction, please provide a link to the incorrect documentation. If this is a new documentation request, please link to where you have looked.

https://nvidia.github.io/cccl/thrust/api/function_group__sorting_1ga2e7ee14dd2878ad63ec1d6156a44e1a1.html
https://nvidia.github.io/cccl/thrust/api/function_group__sorting_1ga77581e28069f26d1c21fc6c3f9d35b25.html