Down_std.EditorEditor interaction.
val find : unit -> (Cmd.t, string) Stdlib.resultfind () finds an editor command in EDITOR or VISUAL (in that order). Does not check it's runnable.
edit_string ~ext s edits strings s in a temporary file with extension ext with an editor found using find (). The resulting string is String.trimed.
edit_file s edits file s with an editor found using find.