must gather attribute fix

Signed-off-by: Shruti Deshpande <shdeshpa@redhat.com>

Author: shdeshpa07

modules/using-must-gather.adoc

@@ -16,7 +16,7 @@ The `must-gather` tool generates a Markdown output file with the collected infor
 
 For more information about the supported flags, use the help flag with the `must-gather` tool as shown in the following example:
 
-[source,terminal]
+[source,terminal,subs="attributes+"]
 ----
 $ oc adm must-gather --image={must-gather-v1-5} -- /usr/bin/gather -h
 ----