fix piantor json

Author: trgsv

config/piantor_pro_bt.json

@@ -97,7 +97,7 @@
                 { "x": 8.45, "y": 3.6, "r": -5.0, "rx": 8.5, "ry": 3.5 },
                 { "x": 9.75, "y": 3.5, "r": 5.0, "rx": 9.75, "ry": 3.5 }
             ]
-        },
+        }
     },
     "sensors": []
 }