Update source/applications/replication.txt

s/tag sets/tags/

Author: monkey101

source/applications/replication.txt

@@ -337,8 +337,8 @@ set for a read operation may resemble the following:
 
    { "disk": "ssd", "use": "reporting" }
 
-To fulfill the request, a member would need to have both of these tag
-sets. Therefore the following tag sets, would satisfy this
+To fulfill the request, a member would need to have both of these tags.
+Therefore the following tag sets, would satisfy this
 requirement:
 
 .. code-block:: javascript