Improve docs for NVTX build requirements

[ZiqiFrancisFan]

What is your question? I noticed that in ranges.hpp, the following inclusion is needed: #include <nvtx3/nvtx3.hpp>. It seems to be that nvtx3.hpp is not even available in cuda-12.3.

[vyasr]

The C++ API of nvtx has unfortunately never quite made it into a CTK release. That is something we have raised internally before but it's never been prioritized. If you look at rmm's CMake you'll see that we fetch nvtx3 as part of the build process to get these headers. You can clone the repo yourself here. The relevant tracking issue is this one.

[bdice]

Vyas's answer covers everything I would say here. I'm going to leave this issue open for now. I want to cover this topic better in the docs.