update tiflash_hashagg_preaggregation_mode

releases/release-8.3.0.md

@@ -221,7 +221,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.3/quick-start-with-
 | [`tidb_enable_lazy_cursor_fetch`](/system-variables.md#tidb_enable_lazy_cursor_fetch-new-in-v830) | Newly added | Controls the behavior of the [Cursor Fetch](/develop/dev-guide-connection-parameters.md#use-streamingresult-to-get-the-execution-result) feature. |
 | [`tidb_enable_shared_lock_upgrade`](/system-variables.md#tidb_enable_shared_lock_upgrade-new-in-v830)       | Newly added  | Controls whether to enable the function of upgrading shared locks to exclusive locks. The default value of this variable is `OFF`, which means that the function of upgrading shared locks to exclusive locks is disabled. |
 | [`tidb_low_resolution_tso`](/system-variables.md#tidb_low_resolution_tso) | Modified | Adds the GLOBAL scope. |
-| [`tiflash_hashagg_preaggregation_mode`](/system-variables.md#tiflash_hashagg_preaggregation_mode-new-in-v830) | Newly added | Controls the pre-aggregation strategy used in the first stage of two-stage or three-stage HashAgg operations pushed down to TiFlash. |
+| [`tiflash_hashagg_preaggregation_mode`](/system-variables.md#tiflash_hashagg_preaggregation_mode-new-in-v830) | Newly added | Controls the pre-aggregation strategy used during the first stage of two-stage or three-stage HashAgg operations pushed down to TiFlash. |
 | [`tidb_opt_projection_push_down`](/system-variables.md#tidb_opt_projection_push_down-new-in-v610) | Modified | Adds the GLOBAL scope and the variable value persists to the cluster. Changes the default value from `OFF` to `ON` after further tests, which means that the optimizer is allowed to push `Projection` down to the TiKV coprocessor. |
 | [`tidb_ddl_reorg_batch_size`](/system-variables.md#tidb_ddl_reorg_batch_size)    | Modified   | Adds the SESSION scope.       |
 | [`tidb_ddl_reorg_worker_cnt`](/system-variables.md#tidb_ddl_reorg_worker_cnt)  | Modified   | Adds the SESSION scope.    |