constructor({raw = '', cooked = '', tail = false}) {
    super('TemplateElement');

    this.value = {raw, cooked};
    this.tail = tail;
  }
Create a template literal

@param {Object} cfg
@param {String} cfg.raw As it looks in source, with escapes added
@param {String} cfg.cooked The actual value
@param {Boolean} cfg.tail True to signify the last element in TemplateLiteral