fix ci

system-variables.md

@@ -25,6 +25,7 @@ SET  GLOBAL tidb_distsql_scan_concurrency = 10;
 > **Note:**
 >
 > Several `GLOBAL` variables persist to the TiDB cluster. Some variables in this document have a `Persists to cluster` setting, which can be configured to `Yes` or `No`.
+>
 > - For variables with the `Persists to cluster: Yes` setting, when a global variable is changed, a notification is sent to all TiDB servers to refresh their system variable cache. When you add additional TiDB servers or restart existing TiDB servers, the persisted configuration value is automatically used.
 > - For variables with the `Persists to cluster: No` setting, changes only apply to the local TiDB instance that you are connected to. To retain any values set, you need to specify the variables in your `tidb.toml` configuration file.
 >