docs: update docs

[wzhudev]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[codecov]

Codecov Report

Merging #3625 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3625      +/-   ##
==========================================
- Coverage   95.45%   95.45%   -0.01%     
==========================================
  Files         685      685              
  Lines       14042    14075      +33     
  Branches     1865     1874       +9     
==========================================
+ Hits        13404    13435      +31     
+ Misses        231      230       -1     
- Partials      407      410       +3

Impacted Files	Coverage Δ
components/select/nz-option-container.component.ts	95.34% <0%> (-2.33%)	⬇️
components/carousel/nz-carousel-definitions.ts	100% <0%> (ø)	⬆️
components/i18n/languages/date-picker/sk_SK.ts	100% <0%> (ø)	⬆️
...mponents/select/nz-select-top-control.component.ts	100% <0%> (ø)	⬆️
components/i18n/languages/date-picker/et_EE.ts	100% <0%> (ø)	⬆️
components/core/tree/nz-tree-base.service.ts	94.66% <0%> (ø)	⬆️
components/carousel/nz-carousel.component.ts	93.71% <0%> (ø)	⬆️
...mponents/input-number/nz-input-number.component.ts	97.6% <0%> (+0.01%)	⬆️
components/select/nz-select.component.ts	96.93% <0%> (+0.01%)	⬆️
components/select/nz-select.service.ts	85.77% <0%> (+0.06%)	⬆️
... and 2 more

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[vthinkxie]

LGTM