code: function setNodeRemark(ast, remark, yaml) {
    let index = getNodeEndMark(ast).pointer;
    while (index < yaml.length && yaml[index] !== '#' && yaml[index] !== EOL) {
      ++index;
    }
  
    if (EOL === yaml[index] || index === yaml.length) {
      return yaml.substr(0, index) + ' # ' + remark +
          yaml.substring(index);
    } else {
      while (index < yaml.length && (yaml[index] === '#' || yaml[index] === ' ')) {
        ++index;
      }
      let end = index;
      while (end < yaml.length && yaml[end] !== EOL) {
        ++end;
      }
      return yaml.substr(0, index) + remark +
          yaml.substring(end);
    }
  }
docs: /*
  Sets remark of an AST
  
  @param {Node} ast
  @param {string} remark
  @param {string} yaml
  
  @returns {boolean}