Added note on weight-cache-override (#994)

Added note on serving supported models from a different folder without
re-downloading them.

---------
Co-authored-by: Nicolas Patry <patry.nicolas@protonmail.com>

docs/source/supported_models.md

@@ -28,6 +28,12 @@ AutoModelForCausalLM.from_pretrained(<model>, device_map="auto")`
 AutoModelForSeq2SeqLM.from_pretrained(<model>, device_map="auto")
 ```
 
+If you wish to serve a supported model that already exists on a local folder, just point to the local folder.
+
+```bash
+text-generation-launcher --model-id <PATH-TO-LOCAL-BLOOM>
+``````
+
 
 ## Supported Hardware