Update NAS Overview.md (#2042)

* Update NAS Overview.md

docs/en_US/NAS/Overview.md

@@ -34,10 +34,10 @@ Here are some common dependencies to run the examples. PyTorch needs to be above
 
 |Name|Brief Introduction of Algorithm|
 |---|---|
-| [SPOS](SPOS.md) | [Single Path One-Shot Neural Architecture Search with Uniform Sampling](https://arxiv.org/abs/1904.00420) constructs a simplified supernet trained with an uniform path sampling method, and applies an evolutionary algorithm to efficiently search for the best-performing architectures. |
+| [SPOS's 2nd stage](SPOS.md) | [Single Path One-Shot Neural Architecture Search with Uniform Sampling](https://arxiv.org/abs/1904.00420) constructs a simplified supernet trained with an uniform path sampling method, and applies an evolutionary algorithm to efficiently search for the best-performing architectures. _Note:: SPOS is a two-stage algorithm, whose first stage is one-shot and second stage is distributed, leveraging result of first stage as a checkpoint._|
 
-```eval_rst
-.. Note:: SPOS is a two-stage algorithm, whose first stage is one-shot and second stage is distributed, leveraging result of first stage as a checkpoint.
+```eval_rst	
+.. Note:: SPOS is a two-stage algorithm, whose first stage is one-shot and second stage is distributed, leveraging result of first stage as a checkpoint.	
 ```
 
 ## Use NNI API
@@ -58,4 +58,4 @@ The programming interface of designing and searching a model is often demanded i
 [5]: https://arxiv.org/abs/1703.01041
 
 * To [report a bug](https://github.com/microsoft/nni/issues/new?template=bug-report.md) for this feature in GitHub;
-* To [file a feature or improvement request](https://github.com/microsoft/nni/issues/new?template=enhancement.md) for this feature in GitHub.
+* To [file a feature or improvement request](https://github.com/microsoft/nni/issues/new?template=enhancement.md) for this feature in GitHub.
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