doc: add mirror site #102.

Author: jaywcjlove

README.md

@@ -607,6 +607,8 @@ Quick Reference
 
 由于中国国内访问，时常打不开，你可以访问下面镜像网站(国内打不开的不再收录)。推荐自己的[镜像网站](https://github.com/jaywcjlove/reference/discussions/206#discussion-4625735)
 
+[reference.szsyw.cn](https://reference.szsyw.cn/)<!--rehype:target=_blank-->
+[reference.diglit.cn](https://reference.diglit.cn/)<!--rehype:target=_blank-->
 [hanacloud.site](https://reference.hanacloud.site)<!--rehype:target=_blank-->
 [doc.xyz.sb](https://doc.xyz.sb)<!--rehype:target=_blank-->
 [quickref.cn](https://quickref.cn)<!--rehype:target=_blank-->