Update CONTRIBUTING.md

Author: RichardChukwu

CONTRIBUTING.md

@@ -58,13 +58,14 @@ $ ./gradlew assemble
 ## Testing
 
 ```bash
-# Run integration tests
-$ ./gradlew integrationTest
-```
 $ ./gradlew test
+```
 
-# Some modules have integration tests
+### Some modules have integration tests
+
+```
 $ ./gradlew integrationTest
+```
 
 Follow the Java Instrumentation [Style Guide](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/docs/contributing/style-guideline.md) from the opentelemetry-java-instrumentation repository.