Use `glib::ExitCode` for `gio::ApplicationCommandLine::{exit_status,set_exit_status}`#1779

sdroege merged 2 commits intogtk-rs:maingtk-rs/gtk-rs-core:mainfrom

pjungkamp:gio/application-command-line-fixuppjungkamp/gtk-rs-core:gio/application-command-line-fixupCopy head branch name to clipboard