doc UPDATE clarify sr_delete_item for oper DS

Author: michalvasko

src/sysrepo.h

@@ -951,8 +951,10 @@ int sr_set_item_str(sr_session_ctx_t *session, const char *path, const char *val
  * If ::SR_EDIT_STRICT flag is set the specified node must must exist in the datastore.
  * If the @p path includes the list keys/leaf-list value, the specified instance is deleted.
  * If the @p path of list/leaf-list does not include keys/value, all instances are deleted but there can be no further
- * changes merged into the list, use ::SR_EDIT_ISOLATE in such a case. Neither option is allowed
- * for ::SR_DS_OPERATIONAL.
+ * changes merged into the list, use ::SR_EDIT_ISOLATE in such a case.
+ *
+ * For ::SR_DS_OPERATIONAL, this function deletes the selected node from the session push oper data. To delete the node
+ * from the final operational datastore, use ::sr_discard_items() instead. No option is allowed for this datastore.
  *
  * @param[in] session Session ([DS](@ref sr_datastore_t)-specific) to use.
  * @param[in] path [Path](@ref paths) identifier of the data element to be deleted.