Ruff & mypy linting rules.

[willGraham01]

Adds additional rules to the ignore list as per internal Slack suggestions:

• D105 missing docstrings on magic (dunder) methods - can potentially see the value in having such docstrings in some cases but don't think it should be required as typically their behaviour is obvious and function signature (and so interpretation of arguments) fixed by interface they are implementing
• ANN in tests
• D rules in tests

Also have added exclude = ["tests"] to the tool.mypy config section in the pyproject.toml, for the same reasons as ANN has been ignored.

[willGraham01]

Am not sure why pre-commit has decided to compactify the lines in pyproject.toml, hence why this "looks" like a negative PR.

[matt-graham]

Looks good to me. Also not sure what is going on with the reformatting - I think it's probably the hook for prettier causing the reformatting but why it's suddenly decided to do this I don't know as I've more often had it reformat lists in the opposite more verbose direction. If causes issues / starts flip flopping recommended reformatting changes we can review it's configuration.