Add support to print help/usage of util.parseArgs

What is the problem this feature will solve?

An almost ubiquitous practice of writing a CLI is including a help command in the CLI itself. Currently anyone using util.parseArgs needs to write their own help command. This, in my opinion, makes parseArgs incomplete.

What is the feature you are proposing to solve the problem?

My suggestion is to include the ability to prin help/usage information generated directly from the config given to parseArgs. A minimum would be something along the lines of:

1. Include help text for each ParseArgsOptionConfig to include help text for each option in particula:

foo: {    
 type: 'boolean',    
 short: 'f',   
 help: 'enable foo',
},

2. Add a main help text to the ParseArgsConfig as well, to include details on what the CLI as a whole:

parseArgs({ 
  help: 'Use this command to achieve foo',
  options: {
    // ...
  }
});

3. Add the --help/-h option to print the generated usage information either:

• always add the --help/-h option, and automatically print the usage and exit the process when parsing the args (E.g. how python's builtin argparse does it); this would be a breaking change since it may conflict with other similar options implemented already.
• add a new option to the ParseArgsConfig to enable autogenerated help option if desired

parseArgs({ 
  enableHelp: true,
  help: 'Use this command to achieve foo',
  options: {
    // ...
  }
});

• simply provide a method to print the usage and let the user implement it themselves in userland

const { values, positionals, printUsage } = parseArgs({
  help: 'Use this command to achieve foo',
  options: {
    help: {
      type: "boolean",
      short: "h",
      help: "print command line options and exit"
    }
  }
});
if (values.help) {
  printUsage();
  process.exit(0);
}

What alternatives have you considered?

No response

从 util.parseArgs 入口点开始，检查现有的 ParseArgsConfig 和 ParseArgsOptionConfig 行为。确定应支持哪种帮助生成 API 以及 --help/-h 行为；当选定的设计已针对命令和选项的用法文本实现时，这项工作就完成了。