Change jk keybinds or make them configurable

[chrisgrieser]

In papers as well as vim, j and k scrolls. The fact that they are used to switch files instead goes against that standard.

I'd suggest using some other keybind for switching files, e.g. J and K, while having j and k perform scrolling. (Or make the keybindings configurable altogether.)

[vogler]

In vim j/k moves the cursor line-wise, ctrl-e/ctrl-y scrolls.
Since the focus is on the files, j/k switches files. Same behavior in lazygit, lazydocker, tig, ncdu etc.

[vic]

IMHO the focus is not on files but on diffs, so I'm in favor of using j/k (lowercase) to scroll the current file diff since that is the main operating I want to do: understand the file diff, and using J/K upcase to move on to other files.