docs: fix quick_start.ipynb (#4392)

It seems this file is not rendered correctly, even in `r2`... The reason
is that `<>` is not escaped. I fix it in
deepmodeling/dargs#85.

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## Summary by CodeRabbit

- **New Features**
- Enhanced quick start tutorial for DeePMD-kit, including new sections
and improved clarity.
	- Added code cells and outputs to demonstrate workflow steps.
	- Improved visual presentation with images and better formatting.

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Signed-off-by: Jinzhe Zeng <jinzhe.zeng@rutgers.edu>