fix typo (#15647) (#15650)

system-variables.md

@@ -433,15 +433,15 @@ This variable is an alias for `last_insert_id`.
 - Scope: NONE
 - Default value: ""
 - The location of the certificate authority file (if there is one). The value of this variable is defined by the TiDB configuration item [`ssl-ca`](/tidb-configuration-file.md#ssl-ca).
-   
+
 </CustomContent>
 
 <CustomContent platform="tidb-cloud">
 
 - Scope: NONE
 - Default value: ""
 - The location of the certificate authority file (if there is one). The value of this variable is defined by the TiDB configuration item [`ssl-ca`](https://docs.pingcap.com/tidb/stable/tidb-configuration-file#ssl-ca).
-   
+
 </CustomContent>
 
 ### ssl_cert
@@ -451,15 +451,15 @@ This variable is an alias for `last_insert_id`.
 - Scope: NONE
 - Default value: ""
 - The location of the certificate file (if there is a file) that is used for SSL/TLS connections. The value of this variable is defined by the TiDB configuration item [`ssl-cert`](/tidb-configuration-file.md#ssl-cert).
-   
+
 </CustomContent>
 
 <CustomContent platform="tidb-cloud">
 
 - Scope: NONE
 - Default value: ""
 - The location of the certificate file (if there is a file) that is used for SSL/TLS connections. The value of this variable is defined by the TiDB configuration item [`ssl-cert`](https://docs.pingcap.com/tidb/stable/tidb-configuration-file#ssl-cert).
-   
+
 </CustomContent>
 
 ### ssl_key
@@ -864,9 +864,9 @@ Constraint checking is always performed in place for pessimistic transactions (d
 - Type: Boolean
 - Default value: `OFF`
 - This variable is used to control whether multiple columns or indexes can be altered in one `ALTER TABLE` statement. When the value of this variable is `ON`, only the following multi-schema changes are supported:
-    - Add multiple columns. For example, `ATLER TABLE t ADD COLUMN c1 INT, ADD COLUMN c2 INT;`.
-    - Drop multiple columns. For example, `ATLER TABLE t DROP COLUMN c1, DROP COLUMN c2;`.
-    - Drop multiple indexes. For example, `ATLER TABLE t DROP INDEX i1, DROP INDEX i2;`.
+    - Add multiple columns. For example, `ALTER TABLE t ADD COLUMN c1 INT, ADD COLUMN c2 INT;`.
+    - Drop multiple columns. For example, `ALTER TABLE t DROP COLUMN c1, DROP COLUMN c2;`.
+    - Drop multiple indexes. For example, `ALTER TABLE t DROP INDEX i1, DROP INDEX i2;`.
     - Drop a column covered by a single-column index. For example, `ALTER TABLE t DROP COLUMN c1`, in which the schema contains `INDEX idx(c1)`.
 
 ### tidb_enable_cascades_planner