fix: edit 'reason' transition

[jimdeng92]

• Update 1-js/02-first-steps/16-function-expressions/article.md

目标章节：1-js/02-first-steps/16-function-expressions/article.md

当前上游最新 commit：无

本 PR 所做更改如下：

文件名	参考上游 commit	更改（理由）
article.md	无	修改部分错误

注意，参考上游 commit 是指你所修改的文件，在英文仓库中同名文件的对应 commit，即你此次提交的修改的依据。如果本 PR 你只是提交一个文字或者语句优化，并非根据上游英文仓库的修改而提交的更新，则请填无。

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[leviding]

LGTM.

[leviding]

感谢，已合并。