[llvm] Configure pyright to the documented minimum python version (PR #162952)

[David Spickett via llvm-commits]

DavidSpickett wrote:

The discussion about the minimum version will probably end up with some static analysis like pyright, so let's see what happens with that first (see https://discourse.llvm.org/t/rfc-upgrading-llvm-s-minimum-required-python-version/88605/32).

Not because no upgrade == no extra checks, but because I don't want to distract from the upgrade discussion.

I've been running vermin and fixing a bunch of issues I found that way. I don't know that it does much with type annotations though. So the combination of that and a type checker would be ideal.

https://github.com/llvm/llvm-project/pull/162952