Fix GenerationMixin inheritance for transformers >= 4.50

RNNLMForCausalLM now explicitly inherits from GenerationMixin (in addition to PreTrainedModel), fixing an AttributeError on _extract_generation_mode_kwargs when calling generate() with transformers >= 4.50.

One-line change: class RNNLMForCausalLM(PreTrainedModel, GenerationMixin):

rnnlm_model/modeling_rnnlm.py

@@ -101,7 +101,7 @@ class GRUKerasCompat(nn.Module):
         return output, h.unsqueeze(0)
 
 
-class RNNLMForCausalLM(PreTrainedModel):
+class RNNLMForCausalLM(PreTrainedModel, GenerationMixin):
     """
     RNN-based Causal Language Model for text generation.
     Compatible with HuggingFace TextGenerationPipeline.