message: fix(platform): wider loadImage callback type
diff: @@ -8,8 +8,8 @@ interface Platform {
  measureText(text: string, font?: string): { width: number }
  loadImage(
  src: string,
  - onload: () => void,
  - onerrror: () => void
  + onload: () => void | HTMLImageElement['onload'],
  + onerror: () => void | HTMLImageElement['onerror']
  ): HTMLImageElement
  }
  