不支持配置换行

**Describe the bug**
配置脚本使用换行的方式写，在 whistle 网页端查看 Rules，会发现配置无法写入

**To Reproduce**
Steps to reproduce the behavior:
1. 在 LightProxy 规则配置页面添加一个分组，使用换行语法配置一条规则
2. 点击 LightProxy 右侧的 Whistle，打开 Rules 页面，会发现之前配置的规则没有被写入

- OS: macOS 10.15.4
- LightProxy: 1.1.3

Reproduce the issue from the LightProxy rules configuration page by creating a group with a multiline rule, then inspect how the configuration is handed to the Whistle Rules page. Done means multiline rules are written and appear correctly in Whistle; no source files or tests are named in the issue.

Written by the indexing model from the issue text.