code: function format(git, npm) {
    git = Array.isArray(git) ? git.join('\n') : git;
    npm = Array.isArray(npm) ? npm.join('\n') : npm;
  
    var res = '';
  
    if (git) {
      res += git;
    }
  
    if (npm) {
      res += '\n\n' + comment + '\n'+ npm;
    }
  
    return res;
  }
docs: Rebuild array back into newline delimited,
  merging .gitignore, .npmignore extras &
  comments (expcted output).
  
  @param  {String} `str`
  @return {Array}
  @api private