fix wrong 'custom_task_directory' in python api doc (#671)

Co-authored-by: xgw <xinguang.wxg@alibaba-inc.com>
Co-authored-by: Nathan Habib <30601243+NathanHB@users.noreply.github.com>

Author: 3 people

docs/source/using-the-python-api.mdx

@@ -34,6 +34,7 @@ def main():
     pipeline_params = PipelineParameters(
         launcher_type=ParallelismManager.ACCELERATE,
         env_config=EnvConfig(cache_dir="tmp/"),
+        custom_task_directory=None, # if using a custom task
         # Remove the 2 parameters below once your configuration is tested
         override_batch_size=1,
         max_samples=10
@@ -52,7 +53,6 @@ def main():
         pipeline_parameters=pipeline_params,
         evaluation_tracker=evaluation_tracker,
         model_config=model_config,
-        custom_task_directory=None, # if using a custom task
     )
 
     pipeline.evaluate()