Obtains the texture format of the swapchain for the given window.
Defined in <SDL3/SDL_gpu.h>
SDL_GPUTextureFormat SDL_GetGPUSwapchainTextureFormat(
    SDL_GPUDevice *device,
    SDL_Window *window);| SDL_GPUDevice * | device | a GPU context. | 
| SDL_Window * | window | an SDL_Window that has been claimed. | 
(SDL_GPUTextureFormat) Returns the texture format of the swapchain.
Note that this format can change if the swapchain parameters change.
This function is available since SDL 3.2.0.