refactor(backtop): rewrite with hook

[xrkffgg]

🤔 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?)

🔗 Related issue link

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	refactor with hook
🇨🇳 Chinese	用 react hook 重构

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• 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

[ant-design-bot]

[lgtm-com]

This pull request introduces 1 alert when merging a353b92 into d50cc55 - view on LGTM.com

new alerts:

• 1 for Unneeded defensive code

[codesandbox-ci]

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[xrkffgg]

@hengkx 这个组件你帮忙看看，如果需要什么改动，你直接在这个分支 改吧。

最近网站方面的有点多，这个我暂时顾不上啦。

[lgtm-com]

This pull request introduces 1 alert when merging a0836bc into 53a76f0 - view on LGTM.com

new alerts:

• 1 for Unneeded defensive code

[hengkx]

好 我看看

[codecov]

Codecov Report

Merging #23575 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #23575      +/-   ##
==========================================
- Coverage   98.82%   98.81%   -0.01%     
==========================================
  Files         364      364              
  Lines        7291     7285       -6     
  Branches     2019     1967      -52     
==========================================
- Hits         7205     7199       -6     
  Misses         86       86              

Impacted Files	Coverage Δ
components/back-top/index.tsx	100.00% <100.00%> (ø)

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[afc163]

/rebase

[hengkx]

/rebase

[lgtm-com]

This pull request introduces 1 alert when merging d82f727 into 610807e - view on LGTM.com

new alerts:

• 1 for Unneeded defensive code

[hengkx]

这个pr 怎么了 为什么 我的eslint都失效了

[lgtm-com]

This pull request introduces 1 alert when merging f2a83fd into 610807e - view on LGTM.com

new alerts:

• 1 for Unneeded defensive code

[hengkx]

这个pr 怎么了 为什么 我的eslint都失效了

我的错 弄错 文件夹了

[hengkx]

/rebase

[hengkx]

为什么rebase都是失败

[yoyo837]

因为有冲突

[lgtm-com]

This pull request introduces 1 alert when merging c895e95 into a83143b - view on LGTM.com

new alerts:

• 1 for Unneeded defensive code