[Doc] add type=mysql in smt of flink cdc doc (#37689)

Signed-off-by: hellolilyliuyi <[email protected]>
Signed-off-by: hellolilyliuyi <[email protected]>
(cherry picked from commit 9fbde40)

Author: hellolilyliuyi

docs/en/loading/Flink_cdc_load.md

@@ -177,6 +177,7 @@ To synchronize data from MySQL in real time, the system needs to read data from
 
     ```Bash
     [db]
+    type = mysql
     host = xxx.xx.xxx.xx
     port = 3306
     user = user1
@@ -210,7 +211,8 @@ To synchronize data from MySQL in real time, the system needs to read data from
     flink.starrocks.sink.buffer-flush.interval-ms=15000
     ```
 
-    - `[db]`: MySQL connection information.
+    - `[db]`: information used to access the source database.
+       - `type`: type of the source database. In this topic, the source database is `mysql`.
        - `host`: IP address of the MySQL server.
        - `port`: port number of the MySQL database, defaults to `3306`
        - `user`: username for accessing the MySQL database

docs/zh/loading/Flink_cdc_load.md

@@ -169,6 +169,7 @@ displayed_sidebar: "Chinese"
 
     ```Bash
     [db]
+    type = mysql
     host = xxx.xx.xxx.xx
     port = 3306
     user = user1
@@ -202,7 +203,8 @@ displayed_sidebar: "Chinese"
     flink.starrocks.sink.buffer-flush.interval-ms=15000
     ```
 
-    - `[db]`：MySQL 的连接信息。
+    - `[db]`：源数据库的连接信息。
+        - `type`：源数据库类型，本示例中源数据库为 `mysql`。
         - `host` ：MySQL 所在服务器的 IP 地址。
         - `port`：MySQL 端口号，默认为`3306`。
         - `user` ：用户名。