Add ability to create Icons from embedded resources on Windows (#1410)

* Add IconExtWindows trait

* Move changelog entries to unreleased category

Co-authored-by: Osspial <osspial@gmail.com>

src/platform_impl/linux/mod.rs

@@ -18,6 +18,8 @@ use crate::{
     window::{CursorIcon, Fullscreen, WindowAttributes},
 };
 
+pub(crate) use crate::icon::RgbaIcon as PlatformIcon;
+
 pub mod wayland;
 pub mod x11;