[doc] update hyperlink (vllm-project#16877)

Signed-off-by: reidliu41 <reid201711@gmail.com>
Co-authored-by: reidliu41 <reid201711@gmail.com>
Signed-off-by: Yang Wang <elainewy@meta.com>

Author: reidliu41

docs/source/models/extensions/fastsafetensor.md

@@ -1,5 +1,5 @@
 Loading Model weights with fastsafetensors
 ===================================================================
 
-Using fastsafetensor library enables loading model weights to GPU memory by leveraging GPU direct storage. See https://github.com/foundation-model-stack/fastsafetensors for more details.
+Using fastsafetensors library enables loading model weights to GPU memory by leveraging GPU direct storage. See [their GitHub repository](https://github.com/foundation-model-stack/fastsafetensors) for more details.
 For enabling this feature, set the environment variable ``USE_FASTSAFETENSOR`` to ``true``