azure-storage-file-datalake needs docstring updates for sphinx version 9.1.0

[azure-sdk]

ACTION NEEDED: This version of sphinx will be merged on 2026-04-13. The build will begin to fail for this library if errors are not fixed.

Library name: azure-storage-file-datalake
Sphinx version: 9.1.0
Sphinx Build: Link to build (2026-03-02)
How to fix: Run the next-sphinx tox command at the library package-level and resolve the docstring errors.

1. ../azure-storage-file-datalake>pip install "tox<5"
2. ../azure-storage-file-datalake>tox run -e next-sphinx -c ../../../eng/tox/tox.ini --root .

See the Sphinx and docstring checker for more information.