doc: remove os.uptime() Windows note
The libuv 1.20.2 update in Node 10 aligned the Windows behavior of os.uptime()
with that of other operating systems. The return value no longer contains a fraction component.
Refs: https://github.com/nodejs/node/pull/20129
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
documentation is changed or added -
commit message follows commit guidelines