HHH-11482 Update example and documentation to clarify SUBSTRING is 1-based

documentation/src/main/asciidoc/userguide/chapters/query/hql/HQL.adoc

@@ -1128,7 +1128,8 @@ include::{sourcedir}/HQLTest.java[tags=hql-concat-function-example]
 
 SUBSTRING::
 	  Extracts a portion of a string value.
-	  The second argument denotes the starting position. The third (optional) argument denotes the length.
+	  The second argument denotes the starting position, where 1 is the first character of the string.
+	  The third (optional) argument denotes the length.
 
 ====
 [source, JAVA, indent=0]

documentation/src/test/java/org/hibernate/userguide/hql/HQLTest.java

@@ -1145,7 +1145,7 @@ public class HQLTest extends BaseEntityManagerFunctionalTestCase {
 		doInJPA( this::entityManagerFactory, entityManager -> {
 			//tag::hql-substring-function-example[]
 			List<String> prefixes = entityManager.createQuery(
-				"select substring( p.number, 0, 2 ) " +
+				"select substring( p.number, 1, 2 ) " +
 				"from Call c " +
 				"join c.phone p", String.class )
 			.getResultList();