Improve help text output by the default help subcommand

The help text output by the default help subcommand doesn't seem proper to me:

1. The `USAGE` section doesn't show `-h`, `--help`, or `--version` if they are autogenerated
2. The `USAGE` section doesn't indicate that `` is optional, or that it can be followed by additional arguments
3. The `OPTIONS` section lists `--version` before `-h, --help`, but I think they should be sorted alphabetically
4. The `SUBCOMMANDS` section doesn't show `help … Show help information.`, which I think should be inserted alphabetically in the subcommand list

**ArgumentParser version:**

main

**Swift version:** Paste the output of `swift --version` here.

swift-driver version: 1.127.14.1 Apple Swift version 6.2.1 (swiftlang-6.2.1.4.8 clang-1700.4.4.1)
Target: arm64-apple-macosx26.0

### Checklist
- [x] If possible, I've reproduced the issue using the `main` branch of this package
- [x] I've searched for [existing GitHub issues](https://github.com/apple/swift-argument-parser/issues)

### Steps to Reproduce

Run the `help` subcommand of a command that has both a default `help` subcommand and that has `CommandConfiguration.version` set. They needn't exist together, but doing this shows both problems at once.

### Expected behavior

Top-level help output:

```text
OVERVIEW: Command

USAGE: cmd [(-h | --help) [] | --version | *…]

OPTIONS:
-h, --help Show help information.
--version Show the version.

SUBCOMMANDS:
a A
b B
c C
help Show help information.
```

### Actual behavior

Top-level help output:

```text
OVERVIEW: Command

USAGE: cmd

OPTIONS:
--version Show the version.
-h, --help Show help information.

SUBCOMMANDS:
a A
b B
c C
```

Start by reproducing the default help subcommand with a command that has autogenerated help, a version, and subcommands a, b, and c. Compare the output with the expected example; done means the USAGE, OPTIONS, and SUBCOMMANDS sections include and order the entries described in the issue.

Written by the indexing model from the issue text.