docs: fix defination of se_e3 (#4113)

As discussed in #4066

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## Summary by CodeRabbit


- **Documentation**
- Updated the description of the `se_e3` notation for improved clarity
regarding its relation to three-body embedding in DeepPot-SE.
- Enhanced explanation of bond-angle information in the context of the
embedding.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

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Signed-off-by: Jinzhe Zeng <jinzhe.zeng@rutgers.edu>
Co-authored-by: Han Wang <92130845+wanghan-iapcm@users.noreply.github.com>

doc/model/train-se-e3.md

@@ -4,7 +4,8 @@
 **Supported backends**: TensorFlow {{ tensorflow_icon }}, PyTorch {{ pytorch_icon }}, DP {{ dpmodel_icon }}
 :::
 
-The notation of `se_e3` is short for the Deep Potential Smooth Edition (DeepPot-SE) constructed from all information (both angular and radial) of atomic configurations. The embedding takes bond angles between a central atom and its two neighboring atoms as input (denoted by `e3`).
+The notation of `se_e3` is short for three-body embedding DeepPot-SE, which incorporates embedded bond-angle information.
+The embedding takes bond angles between a central atom and its two neighboring atoms as input (denoted by `e3`).
 
 ## Theory