Add Window::is_minimized

Co-authored-by: Kirill Chibisov <contact@kchibisov.com>
Co-authored-by: Markus Siglreithmaier <m.siglreith@gmail.com>

src/platform_impl/linux/wayland/window/mod.rs

@@ -483,6 +483,11 @@ impl Window {
         self.decorated.load(Ordering::Relaxed)
     }
 
+    #[inline]
+    pub fn is_minimized(&self) -> Option<bool> {
+        None
+    }
+
     #[inline]
     pub fn set_minimized(&self, minimized: bool) {
         // You can't unminimize the window on Wayland.