feat(concurrency): Add comment from feedback

Author: PerfectSlayer

dd-java-agent/instrumentation/java-concurrent/java-concurrent-25/src/main/java/datadog/trace/instrumentation/java/concurrent/structuredconcurrency/StructuredTaskScopeInstrumentation.java

@@ -54,7 +54,8 @@ public void methodAdvice(MethodTransformer transformer) {
   public static final class ConstructorAdvice {
     @Advice.OnMethodExit
     public static <T> void captureScope(
-        @Advice.This Object task // StructuredTaskScopeImpl.SubtaskImpl (can't use the type)
+        @Advice.This Object task // StructuredTaskScopeImpl.SubtaskImpl
+        // (the advice are compile against Java 8 so the type from JDK25 can't be referred)
         ) {
       ContextStore<Object, State> contextStore =
           InstrumentationContext.get(