How to list keys in `--group` using `kreadconfig6`?

[rokejulianlockhart]

@krake

I think it would be a sensible request to add some kind of “list” behavior if the tool is called without full parameters.

E.g. if you just provide the file it lists the groups in that file, if you provide file and group it lists the keys.

@krake, that was how I too expected it to work when I first tried the tool. I’ve filed bugs.kde.org/show_bug.cgi?id=498473#c0.