code: public XHTMLText appendOpenSpanTag(String style) {
          text.halfOpenElement(SPAN);
          text.optAttribute(STYLE, style);
          text.rightAngleBracket();
          return this;
      }
docs: Appends a tag that allows to set the fonts for a span of text.
  
  @param style the style for a span of text
  
  @return this.