## Summary

[Internal design
document](https://www.notion.so/astral-sh/In-editor-settings-19e48797e1ca807fa8c2c91b689d9070?pvs=4)

This PR expands `ruff.configuration` to allow inline configuration
directly in the editor. For example:

```json
{
	"ruff.configuration": {
		"line-length": 100,
		"lint": {
			"unfixable": ["F401"],
			"flake8-tidy-imports": {
				"banned-api": {
					"typing.TypedDict": {
						"msg": "Use `typing_extensions.TypedDict` instead"
					}
				}
			}
		},
		"format": {
			"quote-style": "single"
		}
	}
}
```

This means that now `ruff.configuration` accepts either a path to
configuration file or the raw config itself. It's _mostly_ similar to
`--config` with one difference that's highlighted in the following
section. So, it can be said that the format of `ruff.configuration` when
provided the config map is same as the one on the [playground] [^1].

## Limitations

<details><summary><b>Casing (<code>kebab-case</code> v/s/
<code>camelCase</code>)</b></summary>
<p>


The config keys needs to be in `kebab-case` instead of `camelCase` which
is being used for other settings in the editor.

This could be a bit confusing. For example, the `line-length` option can
be set directly via an editor setting or can be configured via
`ruff.configuration`:

```json
{
	"ruff.configuration": {
        "line-length": 100
    },
    "ruff.lineLength": 120
}
```

#### Possible solution

We could use feature flag with [conditional
compilation](https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute)
to indicate that when used in `ruff_server`, we need the `Options`
fields to be renamed as `camelCase` while for other crates it needs to
be renamed as `kebab-case`. But, this might not work very easily because
it will require wrapping the `Options` struct and create two structs in
which we'll have to add `#[cfg_attr(...)]` because otherwise `serde`
will complain:

```
error: duplicate serde attribute `rename_all`
  --> crates/ruff_workspace/src/options.rs:43:38
   |
43 | #[cfg_attr(feature = "editor", serde(rename_all = "camelCase"))]
   |                                      ^^^^^^^^^^
```

</p>
</details> 

<details><summary><b>Nesting (flat v/s nested keys)</b></summary>
<p>

This is the major difference between `--config` flag on the command-line
v/s `ruff.configuration` and it makes it such that `ruff.configuration`
has same value format as [playground] [^1].

The config keys needs to be split up into keys which can result in
nested structure instead of flat structure:

So, the following **won't work**:

```json
{
	"ruff.configuration": {
		"format.quote-style": "single",
		"lint.flake8-tidy-imports.banned-api.\"typing.TypedDict\".msg": "Use `typing_extensions.TypedDict` instead"
	}
}
```

But, instead it would need to be split up like the following:
```json
{
	"ruff.configuration": {
		"format": {
			"quote-style": "single"
		},
		"lint": {
			"flake8-tidy-imports": {
				"banned-api": {
					"typing.TypedDict": {
						"msg": "Use `typing_extensions.TypedDict` instead"
					}
				}
			}
		}
	}
}
```

#### Possible solution (1)

The way we could solve this and make it same as `--config` would be to
add a manual logic of converting the JSON map into an equivalent TOML
string which would be then parsed into `Options`.

So, the following JSON map:
```json
{ "lint.flake8-tidy-imports": { "banned-api": {"\"typing.TypedDict\".msg": "Use typing_extensions.TypedDict instead"}}}
```

would need to be converted into the following TOML string:
```toml
lint.flake8-tidy-imports = { banned-api = { "typing.TypedDict".msg = "Use typing_extensions.TypedDict instead" } }
```

by recursively convering `"key": value` into `key = value` which is to
remove the quotes from key and replacing `:` with `=`.

#### Possible solution (2)

Another would be to just accept `Map<String, String>` strictly and
convert it into `key = value` and then parse it as a TOML string. This
would also match `--config` but quotes might become a nuisance because
JSON only allows double quotes and so it'll require escaping any inner
quotes or use single quotes.

</p>
</details> 

## Test Plan

### VS Code

**Requires astral-sh/ruff-vscode#702

**`settings.json`**:
```json
{
  "ruff.lint.extendSelect": ["TID"],
  "ruff.configuration": {
    "line-length": 50,
    "format": {
      "quote-style": "single"
    },
    "lint": {
      "unfixable": ["F401"],
      "flake8-tidy-imports": {
        "banned-api": {
          "typing.TypedDict": {
            "msg": "Use `typing_extensions.TypedDict` instead"
          }
        }
      }
    }
  }
}
```

Following video showcases me doing the following:
1. Check diagnostics that it includes `TID`
2. Run `Ruff: Fix all auto-fixable problems` to test `unfixable`
3. Run `Format: Document` to test `line-length` and `quote-style`


https://github.com/user-attachments/assets/0a38176f-3fb0-4960-a213-73b2ea5b1180

### Neovim

**`init.lua`**:
```lua
require('lspconfig').ruff.setup {
  init_options = {
    settings = {
      lint = {
        extendSelect = { 'TID' },
      },
      configuration = {
        ['line-length'] = 50,
        format = {
          ['quote-style'] = 'single',
        },
        lint = {
          unfixable = { 'F401' },
          ['flake8-tidy-imports'] = {
            ['banned-api'] = {
              ['typing.TypedDict'] = {
                msg = 'Use typing_extensions.TypedDict instead',
              },
            },
          },
        },
      },
    },
  },
}
```

Same steps as in the VS Code test:



https://github.com/user-attachments/assets/cfe49a9b-9a89-43d7-94f2-7f565d6e3c9d

## Documentation Preview



https://github.com/user-attachments/assets/e0062f58-6ec8-4e01-889d-fac76fd8b3c7



[playground]: https://play.ruff.rs

[^1]: This has one advantage that the value can be copy-pasted directly
into the playground

## Summary

fixup from #702 

## Test Plan

Verified that `null` (not setting `ruff.configuration`) doesn't give me
the warning.