docs: fix import method text in create dataset guide #578

Description

In the documentation page Create dataset, the text above the local data import screenshot says:

如果导入方式是 数据更新与追加，你需要确保列映射关系符合预期。

However, the highlighted import method in the screenshot is 全量覆盖. The text should match the selected import method.

Expected

The sentence should say:

如果导入方式是 全量覆盖，你需要确保列映射关系符合预期。

Actual

The sentence currently says:

如果导入方式是 数据更新与追加，你需要确保列映射关系符合预期。

Additional context

The product UI option itself appears to be correct: the import method option is labeled 全量覆盖. This looks like a documentation content typo rather than a frontend runtime issue.