docs: document dumi dev server port

Author: afc163

README.md

@@ -15,7 +15,6 @@
 
 <p align="center">English | <a href="./README.zh-CN.md">简体中文</a></p>
 
-
 ## Highlights
 
 | Area      | Support                                                   |
@@ -171,6 +170,8 @@ npm run lint
 npm run compile
 ```
 
+The dumi site runs at `http://localhost:8000` by default.
+
 ## Release
 
 ```bash

README.zh-CN.md

@@ -164,6 +164,8 @@ npm run lint
 npm run compile
 ```
 
+dumi 站点默认运行在 `http://localhost:8000`。
+
 ## 发布
 
 ```bash