Where do I find type definitions for a Forge trigger function

Forge
2

if you mean the definitions in manifest yml or index.tsx

modules:
  trigger:
    - key: comment-creation-trigger
      function: comment-create-func
      events:
        - avi:confluence:created:comment

export async function listenCommentCreate(event, context) {
    const pageID = event.content.container.id;
    const commentID = event.content.id;
    const spaceId = event.content.space.id;
 

    return {"msg": "event received"};
}