add Gemma2 models

Former-commit-id: 8fc5a248ecfd6861cb90dac6c14fe89cdeaf8921

src/llamafactory/extras/constants.py

@@ -507,6 +507,18 @@ register_model_group(
         "Gemma-1.1-7B-Chat": {
             DownloadSource.DEFAULT: "google/gemma-1.1-7b-it",
         },
+        "Gemma-2-9B": {
+            DownloadSource.DEFAULT: "google/gemma-2-9b",
+        },
+        "Gemma-2-27B": {
+            DownloadSource.DEFAULT: "google/gemma-2-27b",
+        },
+        "Gemma-2-9B-Chat": {
+            DownloadSource.DEFAULT: "google/gemma-2-9b-it",
+        },
+        "Gemma-2-27B-Chat": {
+            DownloadSource.DEFAULT: "google/gemma-2-27b-it",
+        },
     },
     template="gemma",
 )

src/llamafactory/train/rm/trainer.py

@@ -105,7 +105,7 @@ class PairwiseTrainer(Trainer):
         Subclass and override to inject custom behavior.
 
         Note that the first element will be removed from the output tuple.
-        See: https://github.com/huggingface/transformers/blob/v4.39.1/src/transformers/trainer.py#L3777
+        See: https://github.com/huggingface/transformers/blob/v4.40.0/src/transformers/trainer.py#L3842
         """
         # Compute rewards
         _, _, values = model(**inputs, output_hidden_states=True, return_dict=True)