lib: fix typo in timers insert function comment

PR-URL: https://github.com/nodejs/node/pull/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>