expandedRow hover style should built in Nested tables

[ycjcl868]

Description

If I don't add the .components-table-demo-nested .ant-table-expanded-row:hover > td { background: #fbfbfb; } in my project, I might think expanded row is a bug when hovered.

Screenshot

Reproduce

https://codesandbox.io/s/x972o75k1p

Expection

[zombieJ]

expandedRowRender 支持 hover 加上 Table 本身背景是没有颜色的，联合起来效果的确挺诡异的。但是这个更偏使用场景，不能算是 antd 的问题。让用户给内嵌的 table 加 class 吧

[ycjcl868]

感觉可以在官网例子注明下，很多用户 会误以为是 bug

[afc163]

可以给内嵌 Table 加上背景色。

[zombieJ]

要加顺便给 Header 也搞个颜色吧，否则也不好看：https://codesandbox.io/s/n3yvkllzzp

[yp]

I have an issue introduced by commit 2aefdda.
I have a table inside a card which is shown in the expandedRowRenderer of another table. Everything was fine in 3.10.3, but with 3.10.4 (which introduced the negative margins), the inner table expands outside the card body. Do you really think that having such margins by default is a good choice?

[afc163]

@yp Can you describe your problem in a new issue with reproducible demo?

[afc163]

2aefdda#commitcomment-31218053