Modify api spec description of create postmortem attachment (#2959)

Co-authored-by: ci.datadog-api-spec <packages@datadoghq.com>

Author: api-clients-generation-pipeline[bot]

.generator/schemas/v2/openapi.yaml

@@ -77857,7 +77857,16 @@ paths:
         If you have any feedback, contact [Datadog support](https://docs.datadoghq.com/help/).'
   /api/v2/incidents/{incident_id}/attachments/postmortems:
     post:
-      description: Create a postmortem attachment for an incident.
+      description: 'Create a postmortem attachment for an incident.
+
+
+        The endpoint accepts markdown for notebooks created in Confluence or Google
+        Docs.
+
+        Postmortems created from notebooks need to be formatted using frontend notebook
+        cells,
+
+        in addition to markdown format.'
       operationId: CreateIncidentPostmortemAttachment
       parameters:
       - description: The ID of the incident

lib/datadog_api_client/v2/api/incidents_api.rb

@@ -561,6 +561,10 @@ def create_incident_postmortem_attachment(incident_id, body, opts = {})
     #
     # Create a postmortem attachment for an incident.
     #
+    # The endpoint accepts markdown for notebooks created in Confluence or Google Docs.
+    # Postmortems created from notebooks need to be formatted using frontend notebook cells,
+    # in addition to markdown format.
+    #
     # @param incident_id [String] The ID of the incident
     # @param body [PostmortemAttachmentRequest] 
     # @param opts [Hash] the optional parameters