Expand the default rule set (#23385)

## Summary

This PR adds the new default rule set in preview. This ended up being
pretty non-invasive because the `DEFAULT_SELECTORS` are only used in one
place where `preview` isn't set to the default value of `false`.

I've currently listed each rule with a separate `RuleSelector`, which I
generated with the script below. I thought about trying to be more
clever by finding the smallest set of prefix selectors that yield the
same rule set, but I figured this would be the easiest way to add and
remove rules in the future anyway.

<details><summary>Script</summary>
<p>

```py
import json
import subprocess
import tomllib
from pathlib import Path
from string import ascii_uppercase

RULES = {
    rule["code"]: rule["linter"]
    for rule in json.loads(
        subprocess.run(
            ["ruff", "rule", "--all", "--output-format=json"],
            check=True,
            text=True,
            capture_output=True,
        ).stdout
    )
}

for code, linter in RULES.items():
    if linter == "Ruff-specific rules":
        RULES[code] = "Ruff"


def kebab_to_pascal(s: str) -> str:
    return "".join(part.title() for part in s.split("-"))


rules = tomllib.loads(Path("proposal.toml").read_text())["lint"]["select"]

for rule in rules:
    linter = kebab_to_pascal(RULES[rule])
    suffix = rule.lstrip(ascii_uppercase)

    prefix = "_"
    match linter:
        case "Flake8Comprehensions":
            suffix = suffix.removeprefix("4")
        case "Pycodestyle":
            prefix = ""
            suffix = rule
        case "Flake8Gettext":
            linter = "Flake8GetText"
        case "Pep8Naming":
            linter = "PEP8Naming"
        case "Pylint":
            prefix = ""
            suffix = rule.removeprefix("PL")
        case "Flake8Debugger":
            suffix = suffix.removeprefix("10")

    print(
        " " * 4,
        f"RuleSelector::rule(RuleCodePrefix::{linter}("
        f"codes::{linter}::{prefix}{suffix})),"
        f" // {rule}",
        sep="",
    )
```

</p>
</details> 

## Test Plan

A new CLI test showing the preview default rules. I filtered down the
snapshot to just the `linter.rules.enabled` section, which isn't
strictly necessary but was a lot shorter. I also tested manually in VS
Code to make sure I didn't miss wiring up the preview defaults in the
server:

<img width="681" height="340" alt="image"
src="https://github.com/user-attachments/assets/9f7a0cd4-968e-40d6-abf0-dfbfa496531d"
/>


I also tested in the playground.

Author: ntBre

README.md

@@ -300,7 +300,7 @@ ruff check --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"
 ```
 
 To opt in to the latest lint rules, formatter style changes, interface updates, and more, enable
-[preview mode](https://docs.astral.sh/ruff/rules/) by setting `preview = true` in your configuration
+[preview mode](https://docs.astral.sh/ruff/preview/) by setting `preview = true` in your configuration
 file or passing `--preview` on the command line. Preview mode enables a collection of unstable
 features that may change prior to stabilization.
 
@@ -311,7 +311,7 @@ for more on the linting and formatting commands, respectively.
 
 <!-- Begin section: Rules -->
 
-**Ruff supports over 800 lint rules**, many of which are inspired by popular tools like Flake8,
+**Ruff supports over 900 lint rules**, many of which are inspired by popular tools like Flake8,
 isort, pyupgrade, and others. Regardless of the rule's origin, Ruff re-implements every rule in
 Rust as a first-party feature.
 
@@ -322,6 +322,12 @@ stylistic rules that overlap with the use of a formatter, like `ruff format` or
 If you're just getting started with Ruff, **the default rule set is a great place to start**: it
 catches a wide variety of common errors (like unused imports) with zero configuration.
 
+In [preview](https://docs.astral.sh/ruff/preview/), Ruff enables an expanded set of default rules
+that includes rules from the `B`, `UP`, and `RUF` categories, as well as many more. If you give the
+new defaults a try, feel free to leave feedback in the [GitHub
+discussion](https://github.com/astral-sh/ruff/discussions/23203), where you can also find the new
+rule set listed in full.
+
 <!-- End section: Rules -->
 
 Beyond the defaults, Ruff re-implements some of the most popular Flake8 plugins and related code