bug: 文档中 Maven 镜像配置示例使用了 Groovy 语法，在 Kotlin DSL（`.kts`）下无法编译。

[TPAXcc]

先决条件 (Prerequisites)

• 我已确认这个问题没有在其他 issues中提出过。
  I am sure that this problem has NEVER been discussed in other issues.

发生了什么（What happened）

PS D:\Workspace\Project\intelligentFlows\chat_keystone\app> flutter run -d 192.168.1.8
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
Launching lib\main.dart on 24129RT7CC in debug mode...
e: file:///D:/Workspace/Project/intelligentFlows/chat_keystone/app/android/build.gradle.kts:5:21: Unexpected tokens (use ';' to separate expressions on the same line)

FAILURE: Build failed with an exception.

* Where:
Build file 'D:\Workspace\Project\intelligentFlows\chat_keystone\app\android\build.gradle.kts' line: 5

* What went wrong:
Script compilation error:

  Line 5:         maven { url 'https://mirrors.cernet.edu.cn/flutter/download.flutter.io' }
                              ^ Unexpected tokens (use ';' to separate expressions on the same line)

1 error

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to generate a Build Scan (Powered by Develocity).
> Get more help at https://help.gradle.org.

BUILD FAILED in 4s
Running Gradle task 'assembleDebug'...                              4.8s
Error: Gradle task assembleDebug failed with exit code 1

期望的现象（What you expected to happen）

PS D:\Workspace\Project\intelligentFlows\chat_keystone\app> flutter run -d 192.168.1.8
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
Launching lib\main.dart on 24129RT7CC in debug mode...
Flutter assets will be downloaded from https://storage.flutter-io.cn. Make sure you trust this source!
Running Gradle task 'assembleDebug'...                                 ⣷

如何重现此问题（How to reproduce it）

将maven { url 'https://mirrors.cernet.edu.cn/flutter/download.flutter.io' }添加到flutter build.gradle.kts

操作系统（OS Version）

No response

浏览器（如果适用）（Browser version, if applicable）

No response

其他环境（Other environments）

No response

其他需要说明的事项（Anything else we need to know）

No response