typings: sync JSDoc with the actual implementation

JSDoc comment did not match the actual implementation of
`FileHandle#readableWebStream`.

Refs: https://github.com/nodejs/node/pull/46933
PR-URL: https://github.com/nodejs/node/pull/48853
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Deokjin Kim <deokjin81.kim@gmail.com>

lib/internal/fs/promises.js

@@ -255,6 +255,9 @@ class FileHandle extends EventEmitter {
   /**
    * @typedef {import('../webstreams/readablestream').ReadableStream
    * } ReadableStream
+   * @param {{
+   *   type?: string;
+   *   }} [options]
    * @returns {ReadableStream}
    */
   readableWebStream(options = kEmptyObject) {