code: public HTMLGen directive(String tag, String ... attrs) {
  		forward.append('<');
  		forward.append(tag);
  		addAttrs(attrs);
  		forward.append('>');
  		if(pretty) {
  			forward.println();
  		}
  		return this;
  	}
docs: Use "directive" to handle non-ended HTML tags like <meta ... >  and <link ...>
  @param tag
  @param attrs
  @return