Simplify the jupyter kernelspec setup

[davidorme]

Description

This removes the redundant step of creating a specific pyrealm_python3 kernel for Jupyter notebooks and falls back on the poetry shell and poetry run commands updating the Jupyter kernel specs when run.

I have also added jupytext --pipe black as a pre-commit hook on the docs/source tree to add automatic black formatting of code cell contents, and also ensure consistent formatting of {code-cell} directives (omits the default language)

There is one downside of this, which is that black insists on stripping out semi-colons, which are a recognized (but hacky) way to suppress the printing of matplotlib function return values.

Fixes #246

Type of change

• [ ] New feature (non-breaking change which adds functionality)
• [x] Optimization (back-end change that speeds up the code)
• [ ] Bug fix (non-breaking change which fixes an issue)

Key checklist

• [x] Make sure you've run the pre-commit checks: $ pre-commit run -a
• [x] All tests pass: $ poetry run pytest

Further checks

• [ ] Code is commented, particularly in hard-to-understand areas
• [ ] Tests added that prove fix is effective or that feature works

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 95.23%. Comparing base (050c517) to head (7579dd5). Report is 122 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #247 +/- ## ======================================== Coverage 95.23% 95.23% ======================================== Files 28 28 Lines 1701 1701 ======================================== Hits 1620 1620 Misses 81 81 ```

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[davidorme]

Just to note that this retains black for one pre-commit hook. There doesn't seem to be an equivalent approach for using ruff with jupytext at present. See: https://github.com/astral-sh/ruff/issues/8800