[DOC]: Fix dynamic shared memory reference link

[gevtushenko]

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this bug and that I agree to the Code of Conduct

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

Update

Describe the incorrect/future/missing documentation

There are a few remaining //! <a href="../../examples/block/example_block_reduce_dyn_smem.cu">example_block_reduce_dyn_smem.cu</a> in block radix and merge sort which should be updated to sphinx references.

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/cub/api/classcub_1_1BlockRadixSort.html#classcub_1_1blockradixsort