docs: fix ack error doc (#3869)

Signed-off-by: Song Gao <disxiaofei@163.com>

Author: Yisaer

docs/en_US/extension/portable/python_sdk.md

@@ -83,7 +83,7 @@ When `requireAck` is enabled, the user's custom sink plugin **must** return an a
 }
 ```
 
-Sink implementation must call `ctx.ack_ok()` or `ctx.ack_err(msg)` to return acknowledge. In the following example , the
+Sink implementation must call `ctx.ack_ok()` or `ctx.ack_error(msg)` to return acknowledge. In the following example , the
 collect function inside sink returns ack after handling the data.
 
 ```python
@@ -93,6 +93,13 @@ def collect(self, ctx: Context, data: Any):
         ctx.ack_ok()
 ```
 
+```python
+def collect(self, ctx: Context, data: Any):
+        print('receive: ', data)
+        # only add ack when using with requireAck in the rule
+        ctx.ack_error('error msg')
+```
+
 Function interface:
 
 ```python

docs/zh_CN/extension/portable/python_sdk.md

@@ -82,7 +82,7 @@ sink 时可以配置是否等待 ack 再发送下一条数据。例如，假设
 }
 ```
 
-Sink 插件中调用 `ctx.ack_ok()` 或 `ctx.ack_err(msg)` 返回 ack 信息。以下为示例 collect 函数，调用成功时返回 ack 。
+Sink 插件中调用 `ctx.ack_ok()` 或 `ctx.ack_error(msg)` 返回 ack 信息。以下为示例 collect 函数，调用成功时返回 ack 。
 
 ```python
 def collect(self, ctx: Context, data: Any):
@@ -91,6 +91,13 @@ def collect(self, ctx: Context, data: Any):
         ctx.ack_ok()
 ```
 
+```python
+def collect(self, ctx: Context, data: Any):
+        print('receive: ', data)
+        # only add ack when using with requireAck in the rule
+        ctx.ack_error('error msg')
+```
+
 函数接口:
 
 ```python