[Improve][Doc] Add GenericDialect support in jdbc doc (#9763)

Author: Hisoka-X

docs/en/connector-v2/sink/Jdbc.md

@@ -94,6 +94,8 @@ Postgres 9.5 version or below,please set it to `postgresLow` to support cdc
 
 The appointed dialect, if it does not exist, is still obtained according to the url, and the priority is higher than the url. For example,when using starrocks, you need set it to `starrocks`. Similarly, when using mysql, you need to set its value to `mysql`.
 
+If one dialect not supported by SeaTunnel, it will use the default dialect `GenericDialect`. Just make sure the driver you provided support the database you want to connect.
+
 #### dialect list
 
 |           | Dialect Name |          |

docs/en/connector-v2/source/Jdbc.md

@@ -208,6 +208,8 @@ int_type_narrowing = false
 
 The appointed dialect, if it does not exist, is still obtained according to the url, and the priority is higher than the url. For example,when using starrocks, you need set it to `starrocks`. Similarly, when using mysql, you need to set its value to `mysql`.
 
+If one dialect not supported by SeaTunnel, it will use the default dialect `GenericDialect`. Just make sure the driver you provided support the database you want to connect.
+
 #### dialect list
 
 |           | Dialect Name |          |

docs/zh/connector-v2/sink/Jdbc.md

@@ -91,6 +91,8 @@ Postgres 9.5及以下版本，请设置为 `postgresLow` 来支持 CDC
 
 指定的方言，如果不存在，仍然按照url获取，优先级高于url。例如，当使用 starrocks 时，你需要将其值设置为 starrocks，同理，当使用mysql时，你需要将其值设置为mysql。
 
+如果 SeaTunnel 不支持某种方言，它将使用默认方言 `GenericDialect`。请确保您提供的驱动程序支持您想要连接的数据库。
+
 #### 示例可选
 
 |           | 方言名称       |          |