doc: fix AES-OCB IV length in SubtleCrypto.supports example

Signed-off-by: anshikakalpana <anshikajain196872@gmail.com>
PR-URL: #63717
Fixes: #63713
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: René <contact.9a5d6388@renegade334.me.uk>

Author: Anshikakalpana

doc/api/webcrypto.md

@@ -499,7 +499,7 @@ const key = await crypto.subtle.deriveKey(
   ['encrypt', 'decrypt'],
 );
 const plaintext = 'Hello, world!';
-const iv = crypto.getRandomValues(new Uint8Array(16));
+const iv = crypto.getRandomValues(new Uint8Array(12));
 const encrypted = await crypto.subtle.encrypt(
   { name: encryptionAlg, iv },
   key,