当App.js引入的组件在return里面不是大写字母开头时报的错误：
Warning: The tag <list> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter. list div App
Warning: The tag <list> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter. list div App解决方法：<list> 改为大写 就好了<List>
