lib: fix typo in timers insert function comment

PR-URL: #33301
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: danbev

lib/internal/timers.js

@@ -338,7 +338,7 @@ function insertGuarded(item, refed, start) {
 }
 
 function insert(item, msecs, start = getLibuvNow()) {
-  // Truncate so that accuracy of sub-milisecond timers is not assumed.
+  // Truncate so that accuracy of sub-millisecond timers is not assumed.
   msecs = MathTrunc(msecs);
   item._idleStart = start;