[Data] Fix "Image file formats" link in Dataset.write_images refere…

…nce (ray-project#38678)

Signed-off-by: Balaji Veeramani <[email protected]>

python/ray/data/dataset.py

@@ -2844,7 +2844,7 @@ def write_images(
  column: The column containing the data you want to write to images.
  file_format: The image file format to write with. For available options,
  see `Image file formats <https://pillow.readthedocs.io/en/latest\
- /handbook/image-file-formats.html>`.
+ /handbook/image-file-formats.html>`_.
  filesystem: The pyarrow filesystem implementation to write to.
  These filesystems are specified in the
  `pyarrow docs <https://arrow.apache.org/docs\