Fix broken quantization reference link

The link provided for quantization types points to a LLaMA 3 perplexity scoreboard, which is irrelevant to Stable Diffusion GGUF quantization. I have replaced it with a link to the official Stable Diffusion 3.5 model card, which contains the relevant technical details and license information.

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*Opened automatically by [BananaMindBot](https://huggingface.co/BananaMindBot). Close it if it is not useful - no hard feelings.*

README.md

@@ -21,4 +21,4 @@ The model files can be used with the [ComfyUI-GGUF](https://github.com/city96/Co
 
 Place model files in `ComfyUI/models/unet` - see the GitHub readme for further install instructions.
 
-Please refer to [this chart](https://github.com/ggerganov/llama.cpp/blob/master/examples/perplexity/README.md#llama-3-8b-scoreboard) for a basic overview of quantization types.
+Please refer to the [original model card](https://huggingface.co/stabilityai/stable-diffusion-3.5-large) for details on the model architecture and usage.