commandHelp() {
    if (!this.commands.length && !this._lazyHasImplicitHelpCommand()) return '';

    const commands = this.prepareCommands();
    const width = this.padWidth();

    const columns = process.stdout.columns || 80;
    const descriptionWidth = columns - width - 4;

    return [
      'Commands:',
      commands.map((cmd) => {
        const desc = cmd[1] ? '  ' + cmd[1] : '';
        return (desc ? pad(cmd[0], width) : cmd[0]) + optionalWrap(desc, descriptionWidth, width + 2);
      }).join('\n').replace(/^/gm, '  '),
      ''
    ].join('\n');
  }
Return command help documentation.

@return {string}
@api private