[Docs] Clarification around cpu.Speed - Does this value change?

[mboudreau]

Describe the bug
Looking at the docs, it seems like it's hinting that this value changes based on load/usage because of the speedMin and speedMax datapoints. However, in all my testing across Linux and windows, laptop and PCs, that value never changes - it only shows the base CPU speed at all time, no matter load or what governor is being used.

To Reproduce
1- si.observe({ cpu: 'speed' }, 1000, (data) => console.log(data.cpu.speed))
2- Try this on Linux/Windows, underload, without, different governer.
3- See the number not change.

Expected behavior
Unclear