Incorrect CLI help message for `--reslice-dir` flag

[yousefmoazzam]

The help message states that the default is to use the output directory for the in-memory reslice (if the dataset store is chosen to be backed by an hdf5 file for a section at runtime):

httomo/httomo/cli.py

Lines 122 to 127 in a6b5df6

	@click.option(
	"--reslice-dir",
	type=click.Path(exists=True, file_okay=False, writable=True, path_type=Path),
	default=None,
	help="Directory for temporary files potentially needed for reslicing (defaults to output dir)",
	)

However, I think this is incorrect; the default value for that flag is None, and the code later says that, if the value is None, then use a temp directory:

httomo/httomo/cli.py

Lines 409 to 411 in a6b5df6

	ctx: AbstractContextManager = nullcontext(reslice_dir)
	if reslice_dir is None:
	ctx = tempfile.TemporaryDirectory()