Fix locale

app/soapbox/locales/en.json

@@ -1197,6 +1197,7 @@
   "soapbox_config.promo_panel.meta_fields.url_placeholder": "URL",
   "soapbox_config.raw_json_hint": "Edit the settings data directly. Changes made directly to the JSON file will override the form fields above. Click Save to apply your changes.",
   "soapbox_config.raw_json_label": "Advanced: Edit raw JSON data",
+  "soapbox_config.raw_json_invalid": "is invalid",
   "soapbox_config.save": "Save",
   "soapbox_config.saved": "Soapbox config saved!",
   "soapbox_config.single_user_mode_hint": "Front page will redirect to a given user profile.",