Fix docs (#1951)

Signed-off-by: Peng Gao <[email protected]>

docs/source/basic_tutorials/notebook.md

@@ -403,7 +403,7 @@ notebook_launcher(training_loop, args, num_processes=2)
 
 In the case of running on multiple nodes, you need to set up a Jupyter session at each node and run the launching cell at the same time.
 
-For an environment containing 2 nodes (computers) with 4 GPUs each and the main computer with an IP address of "172.31.43.8", it would look like so:
+For an environment containing 2 nodes (computers) with 8 GPUs each and the main computer with an IP address of "172.31.43.8", it would look like so:
 
 ```python
 notebook_launcher(training_loop, args, master_addr="172.31.43.8", node_rank=0, num_nodes=2, num_processes=8)