fix: RichText组件selectable类型修改

[xm1769315774]

这个 PR 做了什么? (简要描述所做更改)

这个 PR 是什么类型? (至少选择一个)

• 错误修复(Bugfix) issue: fix #
• 新功能(Feature)
• 代码重构(Refactor)
• TypeScript 类型定义修改(Typings)
• 文档修改(Docs)
• 代码风格更新(Code style update)
• 其他，请描述(Other, please describe):

这个 PR 涉及以下平台:

• 所有小程序
• 微信小程序
• 支付宝小程序
• 百度小程序
• 字节跳动小程序
• QQ 轻应用
• 京东小程序
• 快应用平台（QuickApp）
• Web 平台（H5）
• 移动端（React-Native）
• 鸿蒙（harmony）

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.51%. Comparing base (936c61e) to head (703000a).
Report is 5 commits behind head on 3.x.

Additional details and impacted files

@@           Coverage Diff           @@
##              3.x   #16092   +/-   ##
=======================================
  Coverage   56.51%   56.51%           
=======================================
  Files         500      500           
  Lines       22768    22765    -3     
  Branches     5639     5614   -25     
=======================================
- Hits        12867    12866    -1     
- Misses       8679     8695   +16     
+ Partials     1222     1204   -18     

Flag	Coverage Δ
taro-cli	49.21% <ø> (-25.79%)	⬇️
taro-runner	49.22% <ø> (-4.79%)	⬇️
taro-runtime	79.39% <ø> (ø)
taro-web	40.48% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 11 files with indirect coverage changes

[TheKonka]

感谢贡献