[llvm] [mlir] [mlir python] Add nanobind support for standalone dialects. (PR #117922)

[Stella Laurenzo via llvm-commits]

stellaraccident wrote:

That's a pretty material change, so we should make an RFC. The implementation choices have never been exposed as part of the public API, so I don't expect it to be controversial. But a number of folks do build on this stuff and need to know. 

I'm on vacation and trying to be offline for the next two weeks, but if its after that, I can help smooth anything that needs smoothing. We'll probably also want to give a window for downstream testing to catch anything unexpected. 

If its before that, maks can tune in.

Thanks for the labor. Switching will be a big improvement.

https://github.com/llvm/llvm-project/pull/117922