pre_executed directory is not excluded from pre-commit's sphinx-build #543

# Initialize a new project
copier copy gh:lincc-frameworks/python-project-template -r v2.0.7 new_project
## Select simple and and answer other questions 
cd new_project
python3 -mvenv ~/.virtualenvs/new_project && source ~/.virtualenvs/new_project/bin/activate
bash .initialize_new_project.sh

# Create a notebook which creates Hello.text file on run
python -m pip install jupytext
echo 'print("Hello, world!")' > hello_world.py
python -m jupytext --to ipynb --output docs/pre_executed/hello_world.ipynb hello_world.py
# Test that the does NOT exist
test -f Hello.text && exit 1
test -f docs/pre_executed/Hello.text && exit 1

# Commit and see that notebook has been run
git switch -c new-branch
git add docs/pre_executed/hello_world.ipynb
git commit -m "Hello"

# Fail appeared 
test -f docs/pre_executed/Hello.text && exit 1  # FAILS