Fix typo in sample response JSON in API docs (#4353)

Add missing comma to make the example response valid JSON

Author: rrashidov

docs/v3/source/includes/api_resources/_domains.erb

@@ -95,7 +95,7 @@
 <% content_for :shared_orgs do %>
 {
   "data": [
-    {"guid": "404f3d89-3f89-6z72-8188-751b298d88d5"}
+    {"guid": "404f3d89-3f89-6z72-8188-751b298d88d5"},
     {"guid": "416d3d89-3f89-8h67-2189-123b298d3592"}
   ]
 }