Update Python.gitignore for .ruff_cache/

[csauge]

Add Ruff cache in gitignore.
Ruff is becoming a very popular tool often run in pre-commit and aim to replace Flake8 (plus dozens of plugins), isort, pydocstyle, yesqa, eradicate, pyupgrade, and autoflake, all while executing tens or hundreds of times faster than any individual tool.

Reasons for making this change:
Ruff is run in pre-commit thus .ruff_cache/ could be included accidently in git.
Actually this is similar to .mypy_cache/ which is also run in pre-commit.

Links to documentation supporting these rule changes:
https://github.com/charliermarsh/ruff in section configuration we can see the exclude of .ruff_cache and .mypy_cache

[covracer]

See also #4199

[JasperJuergensen]

I think this is not required, as ruff will add a .gitignore file to the .ruff_cache folder with * as content effectively ignoring the folder.

See astral-sh/ruff#204 and astral-sh/ruff#208

[stdedos]

It is nicer to have it there.

e.g. PyCharm's excluded folders (and https://plugins.jetbrains.com/plugin/17288-foldable-projectview) work based on these ignores

[paduszyk]

@JasperJuergensen pytest does the same - it also adds .gitignore with * to its cache dir. But .pytest_cache it's included in the template... The same regards nox, for instance.

[stankudrow]

I agree that it is nice to have the .ruff_cache directory included like .mypy_cache and .pytest_cache. The ruff project is steadily developing and becoming widespread, so it is good to have it on board.

Also was mentioned in #4199 and #4274 PRs.

For instance, without the .ruff_cache line in my .gitignore file this directory is not grayed:

When added:

[abelcheung]

Other tools like mypy and pytest indeed do add their own .gitignore as a fallback measure, in case top level .gitignore doesn't handle them. But in terms of performance it is always better to add those dirs to top level .gitigore, rather than descending into cache folders and read .gitignore there. And there is visual cue differences noted above.

[stdedos]

Can we get some maintainer focus? e.g. @dooleydevin?

[dooleydevin]

Sorry for the late feedback! LGTM and will with the next update of our templates 😄

I'll handle the merge conflicts here too just to move things along since this PR is a bit old.