Fix non-feature-branches schema example not syntax highlighted

doc/04-schema.md

@@ -903,11 +903,13 @@ An example:
 If you have a testing branch, that is heavily maintained during a testing phase and is
 deployed to your staging environment, normally "composer show -s" will give you `versions : * dev-master`.
 
-If you configure latest-.* as a pattern for non-feature-branches like this:
+If you configure `latest-.*` as a pattern for non-feature-branches like this:
 
-    {
-        "non-feature-branches": ["latest-.*"]
-    }
+```json
+{
+    "non-feature-branches": ["latest-.*"]
+}
+```
 
 Then "composer show -s" will give you `versions : * dev-latest-testing`.