Refactor/narrow array name type

[d-v-b]

Remove the possibility that Array.name is None. In situations when Array.name would be None (i.e., when the array is at the root of the store), it will be the empty string ''.

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
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[d-v-b]

this is a breaking change, but I think it falls into the "wart removal" category..

[dcherian]

Can you add an assert a.name is not None here please?

zarr-python/src/zarr/testing/strategies.py

Lines 153 to 161 in d6508b5

	assert isinstance(a, Array)
	if a.metadata.zarr_format == 3:
	assert a.fill_value is not None
	assert isinstance(root[array_path], Array)
	assert nparray.shape == a.shape
	assert chunks == a.chunks
	assert array_path == a.path, (path, name, array_path, a.name, a.path)
	assert a.basename == name, (a.basename, name)
	assert dict(a.attrs) == expected_attrs

[d-v-b]

Can you add an assert a.name is not None here please?

zarr-python/src/zarr/testing/strategies.py

Lines 153 to 161 in d6508b5

	assert isinstance(a, Array)
	if a.metadata.zarr_format == 3:
	assert a.fill_value is not None
	assert isinstance(root[array_path], Array)
	assert nparray.shape == a.shape
	assert chunks == a.chunks
	assert array_path == a.path, (path, name, array_path, a.name, a.path)
	assert a.basename == name, (a.basename, name)
	assert dict(a.attrs) == expected_attrs

done!

[dcherian]

LGTM. No opinions on backcompat