docs: fix error describe

[nuonuoge]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] 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?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[x] 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[bot]]

Codecov Report

Merging #786 (b43cd51) into master (ae75221) will not change coverage. The diff coverage is n/a.

:exclamation: Current head b43cd51 differs from pull request most recent head 0933571. Consider uploading reports for the commit 0933571 to get more accurate results

@@           Coverage Diff           @@
##           master     #786   +/-   ##
=======================================
  Coverage   87.01%   87.01%           
=======================================
  Files         164      164           
  Lines        6645     6645           
  Branches     1109     1109           
=======================================
  Hits         5782     5782           
  Misses        421      421           
  Partials      442      442           

---

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 ae75221...0933571. Read the comment docs.