Improve help output for options

[radubrehar]

This is the help output for https://www.npmjs.com/package/translana

Usage:
 translana <command> [options]

Commands:
  translate  [--text] [--to] [--from] Translates text from source to target language
  version    Prints the version of the translator
  check      Checks slana is working

Options:
  --help     Show help  [boolean]
  --version  Show version number  [boolean]
  --from  [string]
  --to  [string]
  --text  [string]

Notice the options are all listed, from all commands. This does not reflect the reality, since --from, --to and --text are only available to the translate command.
Ideally, it should be like:

Options:
  --help     Show help  [boolean]
  --version  Show version number  [boolean]
  [translate]
    --from  [string]
    --to  [string]
    --text  [string]