fix eslint error and Descriptions.Item ts define

[chenshuai2144]

🤔 This is a ...

• New feature
• Bug fix
• Site / document update
• Component style update
• TypeScript definition update
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

👻 What's the background?

用 eslint 跑了一遍发现类型有问题

💡 Solution

📝 Changelog

Language	Changelog
🇺🇸 English	fix TypeScript type error
🇨🇳 Chinese	修复 TypeScript 的类型错误

☑️ Self Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

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[codecov]

Codecov Report

Merging #17049 into master will decrease coverage by 0.01%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master   #17049      +/-   ##
==========================================
- Coverage   95.96%   95.95%   -0.02%     
==========================================
  Files         263      263              
  Lines        7340     7341       +1     
  Branches     2009     2009              
==========================================
  Hits         7044     7044              
- Misses        294      295       +1     
  Partials        2        2

Impacted Files	Coverage Δ
components/descriptions/index.tsx	98.63% <50%> (-1.37%)	⬇️

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[chenshuai2144]

换行了一下。测试覆盖率下去了

[afc163]

再次没有在 PR 和 commit message 中关联相关 issue：#16946

[ztplz]

为啥你都用了static你还要

JSX.Element 实际上就是React.ReactElement, 用Item的时候children是string还是会挂吧
ReactNode的范围太广了 用ts的时候你基本写什么都不会错的 但是看代码 你又好像只想把它当element处理

typeof多余了 直接 React.SFC<DescriptionsItemProps>