Fix a typo in Trainer.hyperparameter_search docstring (#9762)

`compute_objectie` => `compute_objective`

src/transformers/trainer.py

@@ -1115,7 +1115,7 @@ class Trainer:
     ) -> BestRun:
         """
         Launch an hyperparameter search using ``optuna`` or ``Ray Tune``. The optimized quantity is determined by
-        :obj:`compute_objectie`, which defaults to a function returning the evaluation loss when no metric is provided,
+        :obj:`compute_objective`, which defaults to a function returning the evaluation loss when no metric is provided,
         the sum of all metrics otherwise.
 
         .. warning::