Remove hard-coded list of values in description

Since the meta-data now provide an explicit support for value hints, we
should not copy/paste them in the description as the IDE is able to
process them any way it wants.

Closes gh-3863

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/JpaProperties.java

@@ -133,9 +133,9 @@ public class JpaProperties {
 		private Class<?> namingStrategy;
 
 		/**
-		 * DDL mode ("none", "validate", "update", "create", "create-drop"). This is
-		 * actually a shortcut for the "hibernate.hbm2ddl.auto" property. Default to
-		 * "create-drop" when using an embedded database, "none" otherwise.
+		 * DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto"
+		 * property. Default to "create-drop" when using an embedded database,
+		 * "none" otherwise.
 		 */
 		private String ddlAuto;