chore: add ruff to dev deps

[JP-Ellis]

The pyproject.toml file contains a [tool.ruff] section, but Ruff is missing from the dev dependencies. I assume this was an oversight and this commits adds it.

I have also taken the opportunity to sort the dev (and old_deps_pins) dependencies in alphabetical order.

[yagebu]

The pre-commit hooks include ruff so pre-commit sets up a separate virtual environment up for it. I don't think it needs to be added to the .venv as well (increased the size by 24MB on my machine).

[JP-Ellis]

The reason for including it in the virtual environment is to ensure that the IDE (VSCode in my case) finds the correct version during development, instead of waiting until I create a commit to realise I made some minor linting mistakes. It also ensures that the IDE uses the same version as the pre-commit, as opposed to a perhaps incompatible version it might find elsewhere. Overall, it just makes for a much nicer developer experience.

As to your comment about the size of the virtual environment; this is purely a dev dependency, and therefore should not impact downstream users of Fava on its own (unless they install fava[dev]...)

[JP-Ellis]

I noticed there's now a merge conflict. Would you like me to update the PR to resolve that? Or is the PR a no-go?

As mentioned above, this would only be a dev dependency and therefore should not impact downstream users of the package. It will only ensure that IDEs can use the same version of ruff as in the pre-commit hook, thereby avoiding linting issues during development (as opposed to waiting for the pre-commit hook to fail).