Add missing comma between JSON members in data-formats.md (#10343)

diff --git a/docs/ingestion/data-formats.md b/docs/ingestion/data-formats.md
index 4ee3181..45562f4 100644
--- a/docs/ingestion/data-formats.md
+++ b/docs/ingestion/data-formats.md
@@ -208,7 +208,7 @@
           "expr": "$.path.to.nested"
         }
       ]
-    }
+    },
     "binaryAsString": false
   },
   ...