pbootcms 如何让序号从3开始循环
operate=** （V2.0.4新增）数字运算（支持+-*/%），如访问量加1000[list:visits operate=+1000]
比如想
<li data-id='3'><img src="/static/upload/image/20220114/1642150911488937.jpg"></li>
<li data-id='4'><img src="/static/upload/image/20220114/1642150836770511.jpg"></li>
<li data-id='5'><img src="/static/upload/image/20220114/1642150586968072.jpg"></li>
id从3 4 5开始循环
{pboot:list scode=1 num=3 start=4}
<li data-id='[list:n operate=+3]'><img src="[list:ico]"></li>
{/pboot:list}
