message: change to "type", per review
diff: "member": {
  "type": {
  "name": "type",
  - "override-type": "WorkerType",
  + "type": "WorkerType",
  "required": 0
  },
  "credentials": {
  "name": "credentials",
  - "override-type": "RequestCredentials",
  + "type": "RequestCredentials",
  "required": 0
  },
  "name": {
  "name": "name",
  - "override-type": "string",
  + "type": "DOMString",
  "required": 0
  }
  }
  