docs: unify and enhance language navigation in all README files

- Unify language navigation format and emphasize the current language in all README files

Signed-off-by: appleboy <[email protected]>

Author: appleboy

README.md

@@ -1,13 +1,13 @@
 # CodeGPT
 
+**English** | [繁體中文](./README.zh-tw.md) | [简体中文](./README.zh-cn.md)
+
 [![Lint and Testing](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml/badge.svg?branch=main)](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml)
 [![codecov](https://codecov.io/gh/appleboy/CodeGPT/branch/main/graph/badge.svg)](https://codecov.io/gh/appleboy/CodeGPT)
 [![Go Report Card](https://goreportcard.com/badge/github.com/appleboy/CodeGPT)](https://goreportcard.com/report/github.com/appleboy/CodeGPT)
 
 ![cover](./images/cover.png)
 
-English | [繁體中文](./README.zh-tw.md) | [简体中文](./README.zh-cn.md)
-
 ## Table of Contents
 
 - [CodeGPT](#codegpt)

README.zh-cn.md

@@ -1,13 +1,13 @@
 # CodeGPT
 
+[English](./README.md) | [繁體中文](./README.zh-tw.md) | **简体中文**
+
 [![Lint and Testing](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml/badge.svg?branch=main)](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml)
 [![codecov](https://codecov.io/gh/appleboy/CodeGPT/branch/main/graph/badge.svg)](https://codecov.io/gh/appleboy/CodeGPT)
 [![Go Report Card](https://goreportcard.com/badge/github.com/appleboy/CodeGPT)](https://goreportcard.com/report/github.com/appleboy/CodeGPT)
 
 ![cover](./images/cover.png)
 
-[English](./README.md) | [繁體中文](./README.zh-tw.md) | 简体中文
-
 ## 目录
 
 - [CodeGPT](#codegpt)

README.zh-tw.md

@@ -1,13 +1,13 @@
 # CodeGPT
 
+[English](./README.md) | **繁體中文** | [简体中文](./README.zh-cn.md)
+
 [![Lint and Testing](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml/badge.svg?branch=main)](https://github.com/appleboy/CodeGPT/actions/workflows/testing.yml)
 [![codecov](https://codecov.io/gh/appleboy/CodeGPT/branch/main/graph/badge.svg)](https://codecov.io/gh/appleboy/CodeGPT)
 [![Go Report Card](https://goreportcard.com/badge/github.com/appleboy/CodeGPT)](https://goreportcard.com/report/github.com/appleboy/CodeGPT)
 
 ![cover](./images/cover.png)
 
-[English](./README.md) | 繁體中文 | [简体中文](./README.zh-cn.md)
-
 ## 目錄
 
 - [CodeGPT](#codegpt)