--show-settings displays active settings in a far more readable format (#9464)

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## Summary

Fixes #8334.

`Display` has been implemented for `ruff_workspace::Settings`, which
gives a much nicer and more readable output to `--show-settings`.

Internally, a `display_settings` utility macro has been implemented to
reduce the boilerplate of the display code.

### Work to be done

- [x] A lot of formatting for `Vec<_>` and `HashSet<_>` types have been
stubbed out, using `Debug` as a fallback. There should be a way to add
generic formatting support for these types as a modifier in
`display_settings`.
- [x] Several complex types were also stubbed out and need proper
`Display` implementations rather than falling back on `Debug`.
- [x] An open question needs to be answered: how important is it that
the output be valid TOML? Some types in settings, such as a hash-map
from a glob pattern to a multi-variant enum, will be hard to rework into
valid _and_ readable TOML.
- [x] Tests need to be implemented.

## Test Plan

Tests consist of a snapshot test for the default `--show-settings`
output and a doctest for `display_settings!`.

crates/ruff_workspace/src/configuration.rs

@@ -25,12 +25,10 @@ use ruff_linter::rule_selector::{PreviewOptions, Specificity};
 use ruff_linter::rules::pycodestyle;
 use ruff_linter::settings::rule_table::RuleTable;
 use ruff_linter::settings::types::{
-    ExtensionMapping, FilePattern, FilePatternSet, PerFileIgnore, PreviewMode, PythonVersion,
-    SerializationFormat, UnsafeFixes, Version,
-};
-use ruff_linter::settings::{
-    resolve_per_file_ignores, LinterSettings, DEFAULT_SELECTORS, DUMMY_VARIABLE_RGX, TASK_TAGS,
+    ExtensionMapping, FilePattern, FilePatternSet, PerFileIgnore, PerFileIgnores, PreviewMode,
+    PythonVersion, SerializationFormat, UnsafeFixes, Version,
 };
+use ruff_linter::settings::{LinterSettings, DEFAULT_SELECTORS, DUMMY_VARIABLE_RGX, TASK_TAGS};
 use ruff_linter::{
     fs, warn_user, warn_user_once, warn_user_once_by_id, RuleSelector, RUFF_PKG_VERSION,
 };
@@ -260,7 +258,7 @@ impl Configuration {
                 line_length,
                 tab_size: self.indent_width.unwrap_or_default(),
                 namespace_packages: self.namespace_packages.unwrap_or_default(),
-                per_file_ignores: resolve_per_file_ignores(
+                per_file_ignores: PerFileIgnores::resolve(
                     lint.per_file_ignores
                         .unwrap_or_default()
                         .into_iter()