Update FA2 exception msg to point to hub discussions (#28161)

* Update FA2 exception msg to point to hub discussions

* Use path for hub url

src/transformers/modeling_utils.py

@@ -1380,8 +1380,9 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin, GenerationMixin, PushToHubMix
         """
         if not cls._supports_flash_attn_2:
             raise ValueError(
-                f"{cls.__name__} does not support Flash Attention 2.0 yet. Please open an issue on GitHub to "
-                "request support for this architecture: https://github.com/huggingface/transformers/issues/new"
+                f"{cls.__name__} does not support Flash Attention 2.0 yet. Please request to add support where"
+                f" the model is hosted, on its model hub page: https://huggingface.co/{config._name_or_path}/discussions/new"
+                " or in the Transformers GitHub repo: https://github.com/huggingface/transformers/issues/new"
             )
 
         if not is_flash_attn_2_available():