shortcut key for 100%

Hi Alfonso, thanks again for the work 👍

I have (for the moment 😜 ) one further suggestion. Similar to KEY_END for reducing the volume to 0% I'd like to have a shortcut for ->100% (eg KEY_POS1) although maybe it would be more intuitive to revert the relation, like

KEY_END -> 100%
KEY_POS1 -> 0%

as 0% feels more like the start of the range and 100% like the end.