Log information about entering and leaving device scope
I was running some rendering examples and I was surprised to see some log messages stating that my device was being forced to Serial. Panicked, I opened up a debugger and set a breakpoint where the device was forced to Serial. Turns out, the device was forced to Serial inside of a `ScopedRuntimeDeviceTracker` (as part of the `ColorTable` operation). However, the log gave no indication that the default devices were restored. To prevent further misunderstandings for myself and others, added some log messages to the `ScopedRuntimeDeviceTracker` to write when the scope is entered and left at the same logging level as that of the announcement that the device is forced.