Fix NAS Cifar10 docs (#1617)

examples/trials/nas_cifar10/README.md

- **Run Neural Network Architecture Search in NNI**	
- ===	
+# Run Neural Architecture Search in NNI
  
 Now we have an NAS example [NNI-NAS-Example](https://github.com/Crysple/NNI-NAS-Example) run in NNI using NAS interface from our contributors.	
 
 We have included its trial code in this folder, and provided example config files to show how to use PPO tuner to tune the trial code.
 
-> Download data
+To prepare for the dataset, please run `cd data && . download.sh`.
+
+Thanks our lovely contributors, and welcome more and more people to join us!
 
-- `cd data && . download.sh`
-- `tar xzf cifar-10-python.tar.gz && mv cifar-batches cifar10`
- 
-Thanks our lovely contributors. 	
- 
-And welcome more and more people to join us!

examples/trials/nas_cifar10/data/download.sh

 wget https://www.cs.toronto.edu/~kriz/cifar-10-python.tar.gz
+tar xzf cifar-10-python.tar.gz && mv cifar-10-batches-py cifar10
\ No newline at end of file