Improve changelog

Author: alex-kulakov

ChangeLog/6.0.12_dev.txt

@@ -1,3 +1,4 @@
 [main] Addressed DataTypeCollection.Add method issue of wrong adding storage-specifid types to the collection
 [main] Addressed rare issue of entities expire management when SessionOption.NonTransactionalReads is on
+[main] Fixed query root (Query.All<T>()) reuse issue which might lead to bad columns mapping and exception
 [sqlserver] Sql error messages for British English are correctly parsed