Polish "Fix syntax errors in docs"

Closes gh-17835

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

@@ -7933,27 +7933,11 @@ for assertions, as follows:
 
 [source,java,indent=0]
 ----
-	import org.junit.Rule;
-	import org.junit.Test;
-	import org.springframework.boot.test.rule.OutputCapture;
-
-	import static org.hamcrest.Matchers.*;
-	import static org.junit.Assert.*;
-
-	public class MyTest {
-
-		@Rule
-		public OutputCapture capture = new OutputCapture();
-
-		@Test
-		public void testName() throws Exception {
-			System.out.println("Hello World!");
-			assertThat(capture.toString(), containsString("World");
-		}
-
-	}
+include::{test-examples}/test/rule/OutputCaptureTests.java[tag=test]
 ----
 
+
+
 [[boot-features-rest-templates-test-utility]]
 ==== TestRestTemplate