Add many missing spaces in adjacent strings (#26751)

Add missing spaces in adjacent strings

examples/legacy/run_language_modeling.py

@@ -149,7 +149,7 @@ class DataTrainingArguments:
         default=-1,
         metadata={
             "help": (
-                "Optional input sequence length after tokenization."
+                "Optional input sequence length after tokenization. "
                 "The training dataset will be truncated in block of this size for training."
                 "Default to the model max input length for single sentence inputs (take into account special tokens)."
             )
@@ -283,7 +283,7 @@ def main():
 
     if config.model_type in ["bert", "roberta", "distilbert", "camembert"] and not data_args.mlm:
         raise ValueError(
-            "BERT and RoBERTa-like models do not have LM heads but masked LM heads. They must be run using the"
+            "BERT and RoBERTa-like models do not have LM heads but masked LM heads. They must be run using the "
             "--mlm flag (masked language modeling)."
         )