Typo in zh-CN chapter5/3: "积累" should be "记录"

## Description

There is a typo in the Simplified Chinese version of Chapter 5, Section 3.

Page:

https://huggingface.co/learn/llm-course/zh-CN/chapter5/3

### Current text

> 含有`None`的积累删除之后,我们可以规范我们的 `condition` 列:

### Expected text

> 含有`None`的记录删除之后，我们可以规范我们的 `condition` 列：

The word `积累` appears to be a typo here. Since the context refers to removing dataset records whose `condition` value is `None`, `记录` would be more appropriate.

## Screenshot

Start at the Simplified Chinese Chapter 5, Section 3 page linked in the issue and search for the quoted sentence containing `积累`. Change that word to `记录` and apply the shown Chinese punctuation, then verify the rendered page matches the expected text.

Written by the indexing model from the issue text.