## Stack Summary
This stack splits `Settings` into `FormatterSettings` and `LinterSettings` and moves it into `ruff_workspace`. This change is necessary to add the `FormatterSettings` to `Settings` without adding `ruff_python_formatter` as a dependency to `ruff_linter` (and the linter should not contain the formatter settings).
A quick overview of our settings struct at play:
* `Options`: 1:1 representation of the options in the `pyproject.toml` or `ruff.toml`. Used for deserialization.
* `Configuration`: Resolved `Options`, potentially merged from multiple configurations (when using `extend`). The representation is very close if not identical to the `Options`.
* `Settings`: The resolved configuration that uses a data format optimized for reading. Optional fields are initialized with their default values. Initialized by `Configuration::into_settings` .
The goal of this stack is to split `Settings` into tool-specific resolved `Settings` that are independent of each other. This comes at the advantage that the individual crates don't need to know anything about the other tools. The downside is that information gets duplicated between `Settings`. Right now the duplication is minimal (`line-length`, `tab-width`) but we may need to come up with a solution if more expensive data needs sharing.
This stack focuses on `Settings`. Splitting `Configuration` into some smaller structs is something I'll follow up on later.
## PR Summary
This PR extracts the linter-specific settings into a new `LinterSettings` struct and adds it as a `linter` field to the `Settings` struct. This is in preparation for moving `Settings` from `ruff_linter` to `ruff_workspace`
## Test Plan
`cargo test`
## Summary
Ensures that we use the same error types and messages. Also renames
those struct to `FormatCommand*` for consistency, and removes the
`FormatCommandResult::Skipped` variant in favor of skipping in the
iterator directly.
## Summary
Returns an exit code of 1 if any files would be reformatted:
```
ruff on charlie/format-check:main [$?⇡] is 📦 v0.0.286 via 🐍 v3.11.2 via 🦀 v1.72.0
❯ cargo run -p ruff_cli -- format foo.py --check
Compiling ruff_cli v0.0.286 (/Users/crmarsh/workspace/ruff/crates/ruff_cli)
Finished dev [unoptimized + debuginfo] target(s) in 1.69s
Running `target/debug/ruff format foo.py --check`
warning: `ruff format` is a work-in-progress, subject to change at any time, and intended only for experimentation.
1 file would be reformatted
ruff on charlie/format-check:main [$?⇡] is 📦 v0.0.286 via 🐍 v3.11.2 via 🦀 v1.72.0 took 2s
❯ echo $?
1
```
Closes#6966.
## Summary
This is similar to `commands::check` vs. `commands::check_stdin`, and
gets the logic out of the parent file (`lib.rs`). It also ensures that
we avoid formatting files that should be excluded when `--force-exclude`
is provided.
