Notebook JSON inconsistency for Google Colab

[dhruvmanila]

I'm not sure if this deserves its own issue, but: Would it be possible to use extend-include = ["*.ipynb"] and ruff format to only re-format the Python code in cells, and not the ipynb file itself?

My users typically edit notebooks in Google Colab. Google Colab uses two-space indentation in the ipynb file, instead of the typical one-space indentation. ruff format currently re-indents with one space. As such, edit history becomes difficult/impossible to track, because effectively every line gets rewritten between the user saving from Google Colab (changing to 2 spaces) and CI running ruff format (changing to 1 space).

Google Colab also puts keys like metadata, nbformat, nbformat_minor at the top of the file, but ruff format moves these to the bottom. ruff format also changes the order of execution_count, outputs, etc.

I would love to be able to opt out of ipynb formatting, so that only the Python code inside cells is reformatted.

Originally posted by @jpmckinney in #5188 (comment)