message: Make FileSystem*Handle additions smaller
diff: }
  },
  "FileSystemFileHandle": {
  - "name": "FileSystemFileHandle",
  "properties": {
  "property": {
  "kind": {
  }
  },
  "FileSystemDirectoryHandle": {
  - "name": "FileSystemDirectoryHandle",
  "properties": {
  "property": {
  "kind": {
  