请修改 Note 标签使用方式

Note 标签的使用方式存在问题。
如果使用超过一个以上的 Note 标签，那么所有的 Note 标签都必须要使用如下方式，才能正确的生成。
```
{% note danger %}
note danger, note danger, note danger
note danger, note danger, note danger
note danger, note danger, note danger
{% endnote %}
```
Next 主题PR [Fixes and improvements #1160](https://github.com/iissnan/hexo-theme-next/pull/1160)

No file or test is named. Start by locating the Note tag documentation and compare its examples with the syntax shown here; done means documenting the required form when multiple Note tags are used, while checking the referenced NexT PR for context.

Written by the indexing model from the issue text.