docs: dark color tool

[ycjcl868]

🤔 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
🇨🇳 Chinese

☑️ 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

---

View rendered docs/spec/dark.md

[ant-design-bot]

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit bcdfc67:

Sandbox	Source
antd reproduction template	Configuration

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit d08f400:

Sandbox	Source
antd reproduction template	Configuration

[codecov]

Codecov Report

Merging #21101 into master will increase coverage by 0.02%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #21101      +/-   ##
==========================================
+ Coverage   97.49%   97.52%   +0.02%     
==========================================
  Files         296      295       -1     
  Lines        6918     6916       -2     
  Branches     1921     1907      -14     
==========================================
  Hits         6745     6745              
+ Misses        173      171       -2

Impacted Files	Coverage Δ
components/progress/Line.tsx	96.66% <ø> (ø)	⬆️
components/tree/Tree.tsx	100% <ø> (ø)	⬆️
components/radio/group.tsx	94.82% <ø> (ø)	⬆️
components/table/util.ts	100% <100%> (ø)	⬆️
components/table/Table.tsx	96.66% <100%> (ø)	⬆️
components/form/FormItem.tsx	99.01% <100%> (ø)	⬆️
components/layout/layout.tsx	92.3% <100%> (ø)	⬆️
components/button/button.tsx	100% <100%> (ø)	⬆️
components/checkbox/Group.tsx	100% <100%> (ø)	⬆️
components/statistic/utils.tsx	100% <100%> (ø)	⬆️
... and 14 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 96376ca...d08f400. Read the comment docs.

[ycjcl868]

/rebase

[ycjcl868]

/rebase