argparse: undocumented `nargs` constants `ONE_OR_MORE`, `OPTIONAL`, `PARSER`, `REMAINDER`, `ZERO_OR_MORE`, `SUPPRESS`

Concerning the possible values of the nargs parameter of add_argument().

The following values are already described in the documentation, so only a mention of the constants is needed:

• OPTIONAL = ?
• ZERO_OR_MORE = *
• ONE_OR_MORE = +

The following constants and their values do not seem to be documented anywhere:

• PARSER
• REMAINDER

SUPPRESS constant was documented for help parameter in https://github.com/python/cpython/issues/53595, but not for nargs.

先查看 argparse 中 ArgumentParser.add_argument() 及其 nargs 參數的文件，然後檢查現有的 help 參數文件如何描述 SUPPRESS。為 issue 中列出的 nargs 常數撰寫文件，包括 OPTIONAL、ZERO_OR_MORE 和 ONE_OR_MORE 的值，以及缺少的 PARSER 和 REMAINDER 描述；當所有列出的常數都已涵蓋時完成。