fix: Specify Generic for readFile ArrayBuffer (fix #2914) (#2915)

Author: samhinshaw

.changes/fs-write-uint8array-arraybuffer.md

@@ -0,0 +1,6 @@
+---
+fs: patch
+fs-js: patch
+---
+
+`readFile` now returns a more specific type `Promise<Uint8Array<ArrayBuffer>>` instead of the default `Promise<Uint8Array<ArrayBufferLike>`

plugins/fs/guest-js/index.ts

@@ -739,7 +739,7 @@ interface ReadFileOptions {
 async function readFile(
   path: string | URL,
   options?: ReadFileOptions
-): Promise<Uint8Array> {
+): Promise<Uint8Array<ArrayBuffer>> {
   if (path instanceof URL && path.protocol !== 'file:') {
     throw new TypeError('Must be a file URL.')
   }