doc: fix code example in ecdh.setPublicKey()

Fixes: #38540
PR-URL: #38542
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/crypto.md

@@ -1401,7 +1401,7 @@ Example (obtaining a shared secret):
 const {
   createECDH,
   createHash,
-} = await crypto('crypto');
+} = await import('crypto');
 
 const alice = createECDH('secp256k1');
 const bob = createECDH('secp256k1');