fix(module: drawer): synchronize code and documentation

[BronzeCui]

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-mobile/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?

[x] 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
[x] No

Other information

[codecov]

Codecov Report

Merging #311 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #311      +/-   ##
==========================================
+ Coverage   89.59%   89.65%   +0.05%     
==========================================
  Files         229      229              
  Lines        6864     6864              
  Branches      560      560              
==========================================
+ Hits         6150     6154       +4     
+ Misses        550      546       -4     
  Partials      164      164

Impacted Files	Coverage Δ
components/drawer/drawer.component.ts	92% <100%> (ø)	⬆️
components/picker/picker.component.ts	82.35% <0%> (+1.76%)	⬆️
components/picker/picker.service.ts	94.44% <0%> (+5.55%)	⬆️

---

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 58e88ca...5a81988. Read the comment docs.

[Guoyuanqiang]

close #309