doc: change offset of example in Buffer.copyBytesFrom

Actual output is different from expected output if offset is 0.
Plus, removed unused importing `Buffer`.
PR-URL: #47606
Reviewed-By: Debadree Chatterjee <debadree333@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Akhil Marsonya <akhil.marsonya27@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>

Author: deokjinkim

doc/api/buffer.md

@@ -581,7 +581,7 @@ contained by the `Blob` is copied only when the `arrayBuffer()` or `text()`
 methods are called.
 
 ```mjs
-import { Blob, Buffer } from'node:buffer';
+import { Blob } from'node:buffer';
 import { setTimeoutasdelay } from'node:timers/promises';
 
 constblob=newBlob(['hello there']);
@@ -608,7 +608,7 @@ blob.text().then(console.log);
 ```
 
 ```cjs
-const { Blob, Buffer } =require('node:buffer');
+const { Blob } =require('node:buffer');
 const { setTimeout:delay } =require('node:timers/promises');
 
 constblob=newBlob(['hello there']);
@@ -1073,7 +1073,7 @@ Copies the underlying memory of `view` into a new `Buffer`.
 
 ```js
 constu16=newUint16Array([0, 0xffff]);
-constbuf=Buffer.copyBytesFrom(u16, 0, 1);
+constbuf=Buffer.copyBytesFrom(u16, 1, 1);
 u16[1] =0;
 console.log(buf.length); // 2
 console.log(buf[0]); // 255