Improve debugging messages

app/streaming/video/ffmpeg-renderers/vt.mm

@@ -253,6 +253,10 @@ public:
     virtual bool prepareDecoderContext(AVCodecContext* context) override
     {
         context->hw_device_ctx = av_buffer_ref(m_HwContext);
+
+        SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION,
+                    "Using VideoToolbox accelerated renderer");
+
         return true;
     }