Clarify that `cpu_info` times are expressed in milliseconds (#60480)
libuv reports times in milliseconds, but the Julia docs and show() use units of
1/Sys.SC_CLK_TCK which is 100 on my laptop. The mismatch might be due
to libuv changeset https://github.com/libuv/libuv/commit/37a8affbd319209fd0d0d96ee4e3002c8ecc5076.
Fixes #53577