Add tracing in integration tests paragraph to the documentation

See gh-31308

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/testing.adoc

@@ -220,15 +220,17 @@ If such test needs access to an `MBeanServer`, consider marking it dirty as well
 
 include::code:MyJmxTests[]
 
-
-
 [[features.testing.spring-boot-applications.metrics]]
 ==== Using Metrics
 Regardless of your classpath, meter registries, except the in-memory backed, are not auto-configured when using `@SpringBootTest`.
 
 If you need to export metrics to a different backend as part of an integration test, annotate it with `@AutoConfigureObservability`.
 
+[[features.testing.spring-boot-applications.tracing]]
+==== Using Tracing
+Regardless of your classpath, tracing is not auto-configured when using `@SpringBootTest`.
 
+If you need tracing as part of an integration test, annotate it with `@AutoConfigureObservability`.
 
 [[features.testing.spring-boot-applications.mocking-beans]]
 ==== Mocking and Spying Beans