Add more 'see also's to header comments in SDL_gpu.h

include/SDL3/SDL_gpu.h

@@ -1421,6 +1421,7 @@ typedef struct SDL_GPUViewport
  *
  * \sa SDL_UploadToGPUTexture
  * \sa SDL_DownloadFromGPUTexture
+ * \sa SDL_GPUTransferBuffer
  */
 typedef struct SDL_GPUTextureTransferInfo
 {
@@ -1439,6 +1440,7 @@ typedef struct SDL_GPUTextureTransferInfo
  *
  * \sa SDL_UploadToGPUBuffer
  * \sa SDL_DownloadFromGPUBuffer
+ * \sa SDL_GPUTransferBuffer
  */
 typedef struct SDL_GPUTransferBufferLocation
 {
@@ -1454,6 +1456,7 @@ typedef struct SDL_GPUTransferBufferLocation
  * \since This struct is available since SDL 3.2.0.
  *
  * \sa SDL_CopyGPUTextureToTexture
+ * \sa SDL_GPUTexture
  */
 typedef struct SDL_GPUTextureLocation
 {
@@ -1475,6 +1478,7 @@ typedef struct SDL_GPUTextureLocation
  * \sa SDL_UploadToGPUTexture
  * \sa SDL_DownloadFromGPUTexture
  * \sa SDL_CreateGPUTexture
+ * \sa SDL_GPUTexture
  */
 typedef struct SDL_GPUTextureRegion
 {
@@ -1495,6 +1499,7 @@ typedef struct SDL_GPUTextureRegion
  * \since This struct is available since SDL 3.2.0.
  *
  * \sa SDL_BlitGPUTexture
+ * \sa SDL_GPUTexture
  */
 typedef struct SDL_GPUBlitRegion
 {
@@ -1721,6 +1726,7 @@ typedef struct SDL_GPUStencilOpState
  *
  * \since This struct is available since SDL 3.2.0.
  *
+ * \sa SDL_SetGPUBlendConstants
  * \sa SDL_GPUColorTargetDescription
  * \sa SDL_GPUBlendFactor
  * \sa SDL_GPUBlendOp
@@ -2121,6 +2127,11 @@ typedef struct SDL_GPUDepthStencilTargetInfo
  * \since This struct is available since SDL 3.2.0.
  *
  * \sa SDL_BlitGPUTexture
+ * \sa SDL_GPUBlitRegion
+ * \sa SDL_GPULoadOp
+ * \sa SDL_FColor
+ * \sa SDL_FlipMode
+ * \sa SDL_GPUFilter
  */
 typedef struct SDL_GPUBlitInfo {
     SDL_GPUBlitRegion source;       /**< The source region for the blit. */