fix: added newlines to satisfy unix convention

[yamaceay]

This PR aims to satisfy the Unix file convention by adding newlines \n to the files with no newlines.

For detection, we can run the following command:

find packages -type f \( ! -name "*.pyc" -not -path "*__pycache__*" -not -path "*.venv*" \) -print0 | xargs -0 -L1 bash -c 'test "$(tail -c 1 "$0")" && echo "No newline: $0" || echo "Newline: $0"'

with 320 out of 861 files not having newline at the end of the file.

After running:

find packages -type f \( ! -name "*.pyc" -not -path "*__pycache__*" -not -path "*.venv*" \) -print0 | xargs -0 -L1 bash -c 'test "$(tail -c 1 "$0")" && echo "" >> $0' 

The number of no-newline files dropped from 320 to 0, and the issue is resolved.

Note: Other directories or top-level scripts are already OK.

[yamaceay]

Maybe we can configure a pre-commit linter to add newlines in the future automatically soon, also within the scope of this PR. What do you think?

[ZhongpinWang]

Maybe we can configure a pre-commit linter to add newlines in the future automatically soon, also within the scope of this PR. What do you think?

Good idea, also it doesn't have to be a pre-commit hook locally, it can also be a workflow to check all the rules and locally newline will be covered by formatter like Ruff? I guess currently there is only pylint as the linter, no auto formatter like Ruff or Black configured.

[ZhongpinWang]

Thanks for improving the code base!