Update README.md

Author: liruilong940607

README.md

@@ -112,10 +112,12 @@ optimizer.step()
 Before running those example scripts, please check the script about which dataset it is needed, and download
 the dataset first.
 
-``` bash
+```bash
 # clone the repo with submodules.
 git clone --recursive git://github.com/KAIR-BAIR/nerfacc/
+```
 
+``` bash
 # Instant-NGP NeRF in 4.5 minutes with reproduced performance!
 # See results at here: https://www.nerfacc.com/en/latest/examples/ngp.html
 python examples/train_ngp_nerf.py --train_split train --scene lego