Pass text input rect to steam deck keyboard invocation

(cherry picked from commit 51dfca813b6c02746c782a1b1f194cde82e9dbb2)

src/video/x11/SDL_x11keyboard.c

@@ -762,7 +762,9 @@ void X11_ShowScreenKeyboard(SDL_VideoDevice *_this, SDL_Window *window, SDL_Prop
             break;
         }
         (void)SDL_snprintf(deeplink, sizeof(deeplink),
-                           "steam://open/keyboard?XPosition=0&YPosition=0&Width=0&Height=0&Mode=%d",
+                           "steam://open/keyboard?XPosition=%i&YPosition=%i&Width=%i&Height=%i&Mode=%d",
+                           window->text_input_rect.x, window->text_input_rect.y,
+                           window->text_input_rect.w, window->text_input_rect.h,
                            mode);
         SDL_OpenURL(deeplink);
         videodata->steam_keyboard_open = true;