[doc] Add icon descriptions for LoRA/PP status

Signed-off-by: reidliu41 <reid201711@gmail.com>

Author: reidliu41

docs/source/models/supported_models.md

@@ -225,6 +225,12 @@ print(output)
 
 ## List of Text-only Language Models
 
+- ✅︎ indicates that the strategy (LoRA or PP) is supported for the model.
+
+- 🚧 indicates that the strategy (LoRA or PP) is planned but not yet supported for the model.
+
+- ⚠️ indicates that the strategy (LoRA or PP) is available but may have known issues or limitations.
+
 ### Generative Models
 
 See [this page](#generative-models) for more information on how to use generative models.