[llvm] [mlir] [MLIR][Python] reland (narrower) type stub generation (PR #157930)

[Maksim Levental via llvm-commits]

makslevental wrote:

> I should not have to remember to activate a venv any time I work on LLVM.

I guess I don't disagree with the essence of this but this is just by virtue of Python and the nature of Python dev, not nanobind. To wit: nanobind is not the only package you would need to get from pip in our requirements.txt: 

https://packages.fedoraproject.org/search?query=ml-dtypes&releases=Fedora+41&releases=Fedora+42&releases=Fedora+43&start=0 

https://github.com/llvm/llvm-project/pull/157930