feat: added new rule for double indentation on function parameters: f…

[pulphix]

Summary

Adds a new formatter option function-parameter-indent that controls the indentation level of wrapped function and method parameters.
The option lives under [tool.ruff.format] (or [format] in ruff.toml) and accepts "single" (current behavior, default) or "double" (one extra indent level), e.g.:

[tool.ruff.format]
function-parameter-indent = "double"

With "double", multi-line parameter lists for functions, methods, and nested functions are indented one level further than the function body, while lambdas are unchanged.
The option is plumbed through ruff_workspace settings/options, exposed in --show-settings, and documented in the generated schema.

Test Plan

• Ran RUFF_UPDATE_SCHEMA=1 cargo test at the repo root to update schemas and validate all tests.
• Verified new formatter behavior via a dedicated unit test in ruff_python_formatter (double-indented async def parameters).
• Updated and re-ran CLI snapshot tests (cargo test -p ruff --test cli) to cover the new formatter.function_parameter_indent field in --show-settings output.
• Updated and re-ran show_settings tests to ensure default and nested-directory settings output includes the new option.

[ntBre]

Thank you for working on this! However, I will close this PR for the same reason as #19921. As Micha said on #19921, the main blocker to this issue is resolving the questions he raised in #8360 (comment), and we haven't had the chance to resolve those design decisions. The work here and in #19921 is still valuable for the future but isn't actionable at the moment.