Missing whitespaces at RuntimeError message
Trailing whitespaces are missing,

https://github.com/huggingface/transformers/blob/31ec2cb2badfbdd4c1ac9c6c9b8a74e974984206/src/transformers/pipelines/__init__.py#L494-L499

so the error message is a little hard to read.

```python
>>> from transformers import pipeline
>>> pipeline(task=None, model=None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../venv/lib/python3.9/site-packages/transformers/pipelines/__init__.py", line 495, in pipeline
    raise RuntimeError(
RuntimeError: Impossible to instantiate a pipeline without either a task or a modelbeing specified.Please provide a task class or a model
```

- Python 3.9.4
- transformers 4.18.0