fix(module:color-picker): optimize demo copywriting and style

[OriginRing]

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

[zorro-bot]

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[codecov]

Codecov Report

Merging #8088 (f48ccb2) into master (24961cc) will increase coverage by 0.00%.
The diff coverage is n/a.

❗ Current head f48ccb2 differs from pull request most recent head ca3341f. Consider uploading reports for the commit ca3341f to get more accurate results

@@           Coverage Diff           @@
##           master    #8088   +/-   ##
=======================================
  Coverage   91.66%   91.66%           
=======================================
  Files         518      518           
  Lines       17786    17786           
  Branches     2808     2808           
=======================================
+ Hits        16303    16304    +1     
+ Misses       1181     1180    -1     
  Partials      302      302           

see 1 file with indirect coverage changes