Use Matchit to Resolve Per-File Settings (#11111)
## Summary
Continuation of https://github.com/astral-sh/ruff/pull/9444.
> When the formatter is fully cached, it turns out we actually spend
meaningful time mapping from file to `Settings` (since we use a
hierarchical approach to settings). Using `matchit` rather than
`BTreeMap` improves fully-cached performance by anywhere from 2-5%
depending on the project, and since these are all implementation details
of `Resolver`, it's minimally invasive.
`matchit` supports escaping routing characters so this change should now
be fully compatible.
## Test Plan
On my machine I'm seeing a ~3% improvement with this change.
```
hyperfine --warmup 20 -i "./target/release/main format ../airflow" "./target/release/ruff format ../airflow"
Benchmark 1: ./target/release/main format ../airflow
Time (mean ± σ): 58.1 ms ± 1.4 ms [User: 63.1 ms, System: 66.5 ms]
Range (min … max): 56.1 ms … 62.9 ms 49 runs
Benchmark 2: ./target/release/ruff format ../airflow
Time (mean ± σ): 56.6 ms ± 1.5 ms [User: 57.8 ms, System: 67.7 ms]
Range (min … max): 54.1 ms … 63.0 ms 51 runs
Summary
./target/release/ruff format ../airflow ran
1.03 ± 0.04 times faster than ./target/release/main format ../airflow
```
