Adding [source,bash] to wrap text.

node_client.asciidoc

@@ -1018,6 +1018,7 @@ Before running the +setup-channels.sh+ script note the following: Wait a minute
 
 Let's run the script to see its effect and then we will look at how it works internally. We use +bash+ to run it as a command:
 
+[source,bash]
 ----
 $ cd code/docker
 $ bash setup-channels.sh