refactor doc

README-CN.md

@@ -14,7 +14,9 @@ Kuiper 可以运行在各类物联网的边缘使用场景中，比如工业物
 
 ## 功能
 
-- 超轻量：核心服务安装包约 3.5MB，初始运行时占用内存约 10MB
+- 超轻量
+
+  - 核心服务安装包约 3.5MB，初始运行时占用内存约 10MB
 
 - 跨平台
 

README.md

@@ -14,7 +14,9 @@ It can be run at various IoT edge use scenarios, such as real-time processing of
 
 ## Features
 
-- Lightweight: Core server package is only about 3MB, initial memory usage is about 10MB
+- Lightweight
+
+  - Core server package is only about 3MB, initial memory usage is about 10MB
 
 - Cross-platform