ENH: Add custom descriptors (such as dtype, nunique, etc.) to Styler output

- [x] closes: #43875 


![Screen Shot 2021-10-24 at 08 52 28](https://user-images.githubusercontent.com/24256554/138583994-6a8debd6-6b8a-4fbb-a697-536b5a6b3590.png)

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<summary>Former example...</summary>

![Screen Shot 2021-10-05 at 23 37 31](https://user-images.githubusercontent.com/24256554/136106494-c770db25-5598-4a6b-8708-1d2654eac8e1.png)
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