Added the "SDL.window.wayland.registry" property

Fixes https://github.com/libsdl-org/SDL/issues/8393

include/SDL3/SDL_video.h

@@ -967,6 +967,7 @@ extern DECLSPEC SDL_Window *SDLCALL SDL_GetWindowParent(SDL_Window *window);
  * "SDL.window.win32.instance" - the HINSTANCE associated with the window
  *
  * On Wayland:
+ * "SDL.window.wayland.registry" - the wl_registry associated with the window
  * "SDL.window.wayland.display" - the wl_display associated with the window
  * "SDL.window.wayland.surface" - the wl_surface associated with the window
  * "SDL.window.wayland.egl_window" - the wl_egl_window associated with the window

src/video/wayland/SDL_waylandwindow.c

@@ -2098,6 +2098,7 @@ int Wayland_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window)
     } /* All other cases will be WAYLAND_SURFACE_UNKNOWN */
 
     SDL_PropertiesID props = SDL_GetWindowProperties(window);
+    SDL_SetProperty(props, "SDL.window.wayland.registry", c->registry);
     SDL_SetProperty(props, "SDL.window.wayland.display", data->waylandData->display);
     SDL_SetProperty(props, "SDL.window.wayland.surface", data->surface);
     SDL_SetProperty(props, "SDL.window.wayland.egl_window", data->egl_window);