code: function(option) {
      if (arg.text.length === 0) {
        // If someone hasn't typed anything, we only show top level commands in
        // the menu. i.e. sub-commands (those with a space in their name) are
        // excluded. We do this to keep the list at an overview level.
        if (option.name.indexOf(' ') === -1) {
          predictions.push(option);
        }
      }
      else {
        // If someone has typed something, then we exclude parent commands
        // (those without an exec). We do this because the user is drilling
        // down and doesn't need the summary level.
        if (option.value.exec != null) {
          predictions.push(option);
        }
      }
    }
docs: Add an option to our list of predicted options