lib: changed var to let

PR-URL: #30427
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

lib/internal/repl/await.js

@@ -100,7 +100,7 @@ function processTopLevelAwait(src) {
     body,
     ancestors: [],
     replace(from, to, str) {
-      for (var i = from; i < to; i++) {
+      for (let i = from; i < to; i++) {
         wrappedArray[i] = '';
       }
       if (from === to) str += wrappedArray[from];