Respect Unicode characters in import sorting

[charliermarsh]

Summary

Ensures that we use the raw identifier as provided in the source code, rather than the normalized Unicode identifier.

This does mean that we treat these as two separate identifiers, and don't merge them, even though Python will treat them as the same symbol:

import numpy as ℂℇℊℋℌℍℎℐℑℒℓℕℤΩℨKÅℬℭℯℰℱℹℴ
import numpy as CƐgHHHhIILlNZΩZKÅBCeEFio

I think that's fine, this is super rare anyway and would likely be confusing for users.

Closes #10528.

Test Plan

cargo test

[AlexWaygood]

This looks correct to me.

I worry that there might be similar issues in other rules that do autofixes -- it seems reasonable to rely on the id of a Name node being the same as in the original source, and then using it for autofixes. So, maybe eagerly normalizing unicode identifiers in the lexer is a bit of a bug magnet now ://

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.