fix merge issue in testing documentation

Author: habuma

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/testing.adoc

@@ -194,6 +194,7 @@ Here is an example of a JUnit test that performs a RAG query over a PDF document
 
 [source,java]
 ----
+@Test
 void testEvaluation() {
     String userText = "Why is the sky blue?";