feature request: shortcut to select last cell

while editing, i often spend a fair amount of time navigating between two cells. it’s pretty slow. sometimes if i do it enough i open a new window so i can just toggle between those cells in the two windows, but that also takes some time/effort to setup. it’d be nice to have a shortcut key which just swapped me back to the last cell i was editing. for me, that would speed up dev a lot.