Add a note to the docs about non-default PU in Jakarta Data repositories

Author: marko-bekhta

docs/src/main/asciidoc/hibernate-orm.adoc

@@ -1817,10 +1817,28 @@ public class MyEntityResource {
         repository.insert(entity);
     }
 
-	// ...
+    // ...
+
+}
+----
+
+[NOTE]
+====
+When working with non-default persistence units, remember to specify the persistence unit name the repository is targeting
+in the `dataStore` attribute of the repository annotation:
 
+[source,java]
+----
+@Repository(dataStore = "other") // <1>
+public interface MyNonDefaultPURepository {
+    // ...
 }
 ----
+1. Pass the name of the non-default persistence unit to the repository annotation (`other` in this example).
+
+Review the https://jakarta.ee/specifications/data/1.0/apidocs/jakarta.data/jakarta/data/repository/repository#dataStore()[Javadoc of the `@Repository` annotation]
+to learn more about the `dataStore` attribute.
+====
 
 Please refer to the corresponding https://hibernate.org/repositories/[Hibernate Data Repositories]
 and https://jakarta.ee/specifications/data/1.0/jakarta-data-1.0[Jakarta Data]