docs: update docs for 2.7

[uyarn]

🤔 这个 PR 的性质是？

• 日常 bug 修复
• 新特性提交
• 文档改进
• 演示代码改进
• 组件样式/交互改进
• CI/CD 改进
• 重构
• 代码风格优化
• 测试用例
• 分支合并
• 其他

🔗 相关 Issue

• [DatePicker] vue2+webpack 常规全局引用，报错（相关同学请检查 Vue 版本号是否为 Vue2.6.x，TD 暂不支持新版本 2.7.x） #1152

💡 需求背景和解决方案

• 增加更多的文档说明 避免用户使用2.7版本使用异常

📝 更新日志

• 本条 PR 不需要纳入 Changelog

☑️ 请求合并前的自查清单

⚠️ 请自检并全部勾选全部选项。⚠️

• 文档已补充或无须补充
• 代码演示已提供或无须提供
• TypeScript 定义已补充或无须补充
• Changelog 已提供或无须提供

[codecov-commenter]

Codecov Report

Merging #1155 (e9b4f04) into develop (a0db0df) will increase coverage by 1.34%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1155      +/-   ##
===========================================
+ Coverage    57.56%   58.90%   +1.34%     
===========================================
  Files          346      404      +58     
  Lines        12828    15009    +2181     
  Branches      2405     2828     +423     
===========================================
+ Hits          7384     8841    +1457     
- Misses        5200     5897     +697     
- Partials       244      271      +27     

Impacted Files	Coverage Δ
src/cascader/interface.tsx	0.00% <0.00%> (-100.00%)	⬇️
src/swiper/props.ts	68.75% <0.00%> (-31.25%)	⬇️
src/dialog/props.ts	70.00% <0.00%> (-30.00%)	⬇️
src/calendar/props.ts	70.00% <0.00%> (-30.00%)	⬇️
src/date-picker/props.ts	70.00% <0.00%> (-30.00%)	⬇️
src/drawer/props.ts	71.42% <0.00%> (-28.58%)	⬇️
src/cascader/props.ts	64.28% <0.00%> (-27.39%)	⬇️
src/pagination/props.ts	72.72% <0.00%> (-27.28%)	⬇️
src/affix/affix.tsx	39.06% <0.00%> (-27.01%)	⬇️
src/popup/props.ts	75.00% <0.00%> (-25.00%)	⬇️
... and 234 more

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