Add GenerationMixin to ConditionalGeneration class

Florence2LanguageForConditionalGeneration has generative capabilities, as `prepare_inputs_for_generation` is explicitly overwritten. However, it doesn't directly inherit from `GenerationMixin`. From 👉v4.50👈 onwards, `PreTrainedModel` will NOT inherit from `GenerationMixin`, and this model will lose the ability to call `generate` and other related functions.
- If you're using `trust_remote_code=True`, you can get rid of this warning by loading the model with an auto class. See https://huggingface.co/docs/transformers/en/model_doc/auto#auto-classes
- If you are the owner of the model architecture code, please modify your model class such that it inherits from `GenerationMixin` (after `PreTrainedModel`, otherwise you'll get an exception).
- If you are not the owner of the model architecture class, please contact the model code owner to update it.

modeling_florence2.py

@@ -28,6 +28,7 @@ from collections import OrderedDict
 from einops import rearrange
 from timm.models.layers import DropPath, trunc_normal_
 
+from transformers import GenerationMixin
 from transformers.modeling_utils import PreTrainedModel
 from transformers.utils import (
     ModelOutput,
@@ -2529,7 +2530,7 @@ class Florence2VisionModelWithProjection(Florence2PreTrainedModel):
     """The FLORENCE2 model which consists of a vision backbone and a language model.""",
     FLORENCE2_START_DOCSTRING,
 )
-class Florence2ForConditionalGeneration(Florence2PreTrainedModel):
+class Florence2ForConditionalGeneration(Florence2PreTrainedModel, GenerationMixin):
     def __init__(self, config: Florence2Config):
         super().__init__(config)
         assert config.vision_config.model_type == 'davit', 'only DaViT is supported for now'