allow to select files not existing with file chooser

[mokurin000]

as title says, I think currently I cannot select output file gracefully with klask

both of rfd and native_dialog provide save single file dialog.

I don't see any Arg derive in clap approciates for this, please tell me if there is one

otherwise, there is some way:

• #[klask(save_file)]

[mokurin000]

user can change working directory and simply type filename. suffix tips is not important, so I closed this issue