chore: use imported type in Downloader constructor (#957)

This is a types-only change. We were already importing the `BlobFilter`
type above, so let's use it!

src/blob-store/downloader.js

@@ -38,7 +38,7 @@ export class Downloader extends TypedEmitter {
   /**
    * @param {import('./index.js').THyperdriveIndex} driveIndex
    * @param {object} [options]
-   * @param {import('../types.js').BlobFilter | null} [options.filter] Filter blobs of specific types and/or sizes to download
+   * @param {BlobFilter | null} [options.filter] Filter blobs of specific types and/or sizes to download
    */
   constructor(driveIndex, { filter } = {}) {
     super()