readClosingTag(){
      const tagName = this.processTagName(readClosingTagName(this.source));
      // console.log(tagName, this.tagsStack.length);
      this.validateClosingTag(tagName);
      // All the text data collected, belongs to current tag.
      if(!this.currentTagDetail.root) this.addTextNode();
      this.outputBuilder.closeTag();
      // Since the tag is closed now, parent tag comes in scope
      this.currentTagDetail = this.tagsStack.pop(); 
    }
read closing paired tag. Set parent tag in scope.
skip a node on user's choice