This is an automated cherry-pick of pingcap#6434

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

sql-statements/sql-statement-create-index.md

@@ -142,9 +142,13 @@ Expression indexes have the same syntax and limitations as in MySQL. They are im
 
 Currently, the optimizer can use the indexed expressions when the expressions are only in the `FIELD` clause, `WHERE` clause, and `ORDER BY` clause. The `GROUP BY` clause will be supported in future updates.
 
-## Associated session variables
+## Associated system variables
 
+<<<<<<< HEAD
 The global variables associated with the `CREATE INDEX` statement are `tidb_ddl_reorg_worker_cnt`, `tidb_ddl_reorg_batch_size` and `tidb_ddl_reorg_priority`. Refer to [system variables](/system-variables.md#tidb_ddl_reorg_worker_cnt) for details.
+=======
+The system variables associated with the `CREATE INDEX` statement are `tidb_ddl_reorg_worker_cnt`, `tidb_ddl_reorg_batch_size`, `tidb_enable_auto_increment_in_generated`, and `tidb_ddl_reorg_priority`. Refer to [system variables](/system-variables.md#tidb_ddl_reorg_worker_cnt) for details.
+>>>>>>> 4167cb44a (Update the related variable description for CREATE INDEX (#6434))
 
 ## MySQL compatibility