UserEmailOption constructor
Implementation
const UserEmailOption({
  super.argPos,
  super.mandatory,
}) : super(
        argName: 'user',
        argAbbrev: 'u',
        customValidator: emailValidator,
        // a bit convoluted due to Dart's const requirements:
        helpText: 'The user email address.'
            '${argPos == 0 ? ' Can be passed as the first argument.' : argPos == 1 ? ' Can be passed as the second argument.' : ''}',
      );