Allow maximizing windows with the button in the title bar (#84)

src/handlers/xdg_shell.rs

@@ -91,15 +91,14 @@ impl XdgShellHandler for State {
     }
 
     fn maximize_request(&mut self, surface: ToplevelSurface) {
-        // FIXME
-
         // The protocol demands us to always reply with a configure,
         // regardless of we fulfilled the request or not
+        self.niri.layout.toggle_full_width();
         surface.send_configure();
     }
 
     fn unmaximize_request(&mut self, _surface: ToplevelSurface) {
-        // FIXME
+        self.niri.layout.toggle_full_width();
     }
 
     fn fullscreen_request(