doc(s3) little improvements and corrections (#16226)

docs/api/s3.md

@@ -150,7 +150,7 @@ const writer = s3file.writer({
   queueSize: 10,
 
   // Upload in 5 MB chunks
-  partSize: 5,
+  partSize: 5 * 1024 * 1024,
 });
 for (let i = 0; i < 10; i++) {
   await writer.write(bigFile);
@@ -614,9 +614,10 @@ const credentials = {
 
 const stat = await S3Client.stat("my-file.txt", credentials);
 // {
+//   etag: "\"7a30b741503c0b461cc14157e2df4ad8\"",
+//   lastModified: 2025-01-07T00:19:10.000Z,
 //   size: 1024,
-//   etag: "1234567890",
-//   lastModified: new Date(),
+//   type: "text/plain;charset=utf-8",
 // }
 ```
 
@@ -661,7 +662,7 @@ const response = await fetch("s3://my-bucket/my-file.txt", {
     endpoint: "https://s3.us-east-1.amazonaws.com",
   },
   headers: {
-    "x-amz-meta-foo": "bar",
+    "range": "bytes=0-1023",
   },
 });
 ```