*: improve INL_HASH_JOIN document about collation incompatibility (pi…

…ngcap#17119)

optimizer-hints.md

@@ -1000,9 +1000,9 @@ EXPLAIN SELECT /*+ INL_JOIN(t1, t2) */ * FROM t1, t2 WHERE t1.id=t2.id AND SUBST
 7 rows in set (0.00 sec)
 ```
 
-#### `INL_JOIN` hint does not take effect due to collation incompatibility
+### `INL_JOIN`, `INL_HASH_JOIN`, and `INL_MERGE_JOIN` hints do not take effect due to collation incompatibility
 
-When the collation of the join key is incompatible between two tables, the `IndexJoin` operator cannot be utilized to execute the query. In this case, the [`INL_JOIN` hint](#inl_joint1_name--tl_name-) does not take effect. For example:
+When the collation of the join key is incompatible between two tables, the `IndexJoin` operator cannot be utilized to execute the query. In this case, the [`INL_JOIN`](#inl_joint1_name--tl_name-), [`INL_HASH_JOIN`](#inl_hash_join), and [`INL_MERGE_JOIN`](#inl_merge_join) hints do not take effect. For example:
 
 ```sql
 CREATE TABLE t1 (k varchar(8), key(k)) COLLATE=utf8mb4_general_ci;