[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

myst_nb/sphinx_ext.py

@@ -7,7 +7,6 @@
 from importlib import resources as import_resources
 import os
 from pathlib import Path
-import sys
 from types import ModuleType
 from typing import Any, Iterator, cast