[refurb] Do not emit diagnostic when loop variables are used outside loop body (FURB122)

[InSyncWithFoo]

Summary

Resolves #15725.

Previously, FURB122 analyzes for loops only at AST level, resulting in false positives, as shown in the linked issue.

With this change, now FURB122 will also analyze for loops at binding level. If a loop variable is used outside of the loop or shadows another variable, no diagnostic will be emitted.

Two-step analysis is necessary since it's possible for for loops not to have any bindings:

with open('file.txt', 'w') as f:
	for () in range(10):
		f.write('line')

Test Plan

cargo nextest run and cargo insta test.

[InSyncWithFoo]

As the rule is now binding-sensitive, existing tests need to be rescoped. This leads to a rather big change, which I have isolated to the first commit.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+0 -2 violations, +0 -0 fixes in 2 projects; 53 projects unchanged)

apache/airflow (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview --select ALL

- docs/exts/extra_files_with_substitutions.py:51:13: FURB122 [*] Use of `output_file.write` in a for loop

latchbio/latch (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- src/latch_cli/services/get_params.py:180:9: FURB122 [*] Use of `f.write` in a for loop

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
FURB122	2	0	2	0	0

[AlexWaygood]

Not a full review yet, just a couple of style nitpicks :-)

[AlexWaygood]

This looks good, thanks. A couple more points below, but nothing major

[AlexWaygood]

Thanks!