Revert "doc: os.uptime() temporary bug notice"

This reverts commit b9ffb82f.

The bug was fixed in libuv 1.41.0.

Refs: https://github.com/libuv/libuv/pull/3072

PR-URL: https://github.com/nodejs/node/pull/38494


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>