docs:RP2 to mention light and deepsleep
Somehow i got the impression that lightsleep and deepsleep were not working on the RP2 devices. Fortunately ghubcoder posted about PR8832, which prompted me to try using lightsleep.
Perhaps the Quick Ref could include this information. It would also be helpful to mention that when using lightsleep one can not debug/develop using rshell or Thonny.
docs/machine: Change sleep to lightsleep and add timeout arguments.
The machine.sleep() function can be misleading because it clashes with time.sleep() which has quite different semantics. So I propose to change it to machine.lightsleep() which shows that it is closer in behaviour to machine.deepsleep(), and update the wording of these functions in an attempt to make them generic.
Also, add an optional argument to these two sleep functions to specify a maximum time to sleep for. This is a common operation and underlying hardware usually has a special way of performing this operation.
The existing machine.sleep() function will remain for backwards compatibility purposes, and it can simply be an alias for machine.lightsleep() without arguments. The behaviour will be the same.
This PR only changes the docs. If it goes through then I'll follow with implementations on the ports that already have these functions.