update servicenow docs

Author: pijiang3

flashduty/en/1. On-call/8. Integrations/8.5 Webhooks/8.5.5 ServiceNow sync.md

@@ -229,6 +229,8 @@ Note: The body configures default receiving fields. If you have custom fields th
     impact: current.getDisplayValue("impact"),
     urgency: current.getDisplayValue("urgency"),
     comments: getLastComment(current.getUniqueValue()),
+<label name='field_mapping' tab='10'>{original.key}: current.getDisplayValue("{original.key}")</label>
+
   };
 
   try {

flashduty/zh/1. On-call/5. 集成引导/8.5 Webhooks/8.5.5 ServiceNow 同步.md

@@ -227,6 +227,8 @@ IncidentWebhookHelper.prototype = {
     impact: current.getDisplayValue("impact"),
     urgency: current.getDisplayValue("urgency"),
     comments: getLastComment(current.getUniqueValue()),
+<label name='field_mapping' tab='10'>{original.key}: current.getDisplayValue("{original.key}")</label>
+
   };
 
   try {