docs: fix emqx-broker.md

docs-cn/20-third-party/09-emq-broker.md

@@ -116,7 +116,7 @@ INSERT INTO test.sensor_data VALUES(
 ## 编写模拟测试程序
 
 ```javascript
-${{#include docs-examples/other/mock.js}}
+{{#include docs-examples/other/mock.js}}
 ```
 
 注意：代码中 CLIENT_NUM 在开始测试中可以先设置一个较小的值，避免硬件性能不能完全处理较大并发客户端数量。

docs-en/20-third-party/09-emq-broker.md

@@ -108,7 +108,7 @@ Finally, click the "Create" button at bottom left corner saving the rule.
 ## Compose program to mock data
 
 ```javascript
-${{#include docs-examples/other/mock.js}}
+{{#include docs-examples/other/mock.js}}
 ```
 
 Note: `CLIENT_NUM` in the code can be set to a smaller value at the beginning of the test to avoid hardware performance be not capable to handle a more significant number of concurrent clients.