add enter and exit methods to groups.

[dikwickley]

Fixes: #2619

TODO:

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/tutorial.rst
• Changes documented in docs/release.rst
• Test coverage is 100% (Codecov passes)
• GitHub Actions have all passed

[normanrz]

Will you also add this for arrays?

[jhamman]

Thanks for picking this up! Let's also get some unit tests for this. It will be important that we exercise this across all stores and establish expectations about behavior after the store has been closed.

[jhamman]

Suggested change

	def __exit__(self) -> None: # noqa: PYI036
	def __exit__(
	self,
	typ: type[BaseException] | None,
	exc: BaseException | None,
	tb: TracebackType | None
	) -> None:

See https://docs.astral.sh/ruff/rules/bad-exit-annotation/

[dikwickley]

updated in d8f7d68. Also added tests.

[jhamman]

Super close. A few suggestions on how to make the tests just a bit better.

[jhamman]

Suggested change

	with Group.open(store) as store:
	with Group.open(store) as g:

[jhamman]

rather than using this private store api, let's try to just to use the group again and make sure it fails.

Suggested change

	assert not store._is_open
	with pytest.raises(ValueError):
	group.attrs['path'] = 'bar'

[jhamman]

also, instead of using Group.open and Group.from_store, can we use zarr.open_group and zarr.create_group? These are the public facing API methods we want most folks to be using.