doc: Modal文档增加afterClose参数描述

[ziluo]

close #3016

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This change is 

[codecov]

Codecov Report

Merging #3023 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #3023   +/-   ##
======================================
  Coverage    60.1%   60.1%           
======================================
  Files          92      92           
  Lines        2246    2246           
  Branches      643     643           
======================================
  Hits         1350    1350           
  Misses        887     887           
  Partials        9       9

Flag	Coverage Δ
#web	60.1% <ø> (ø)	⬆️

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[doxiaodong]

ok