* Declutter and denoise the debug output in general.
* Avoid f-strings. They're nice to look at, but use a lot of ROM, RAM,
and time during formatting.
* Remove all "debug" information from `KMKKeyboard.__repr__`. It's
printed out once at init and the info it gave was useless at that
point. Even more free memory.
* Add a memory footprint debug info after initialization.