fix-spelling-error,-code-bug,-and-improve-test

[TianqiTang1117]

Summary

• Corrected a spelling mistake in the module utilities documentation so it now reads “walking a module,” improving readability
• Fixed the directory creation helper to use mkdtemp correctly and added clarifying comments to avoid ValueError when no path is provided
• Updated index data utilities to use accurate type hints and clarified that sum_by_index performs an aggregation rather than concatenation
• Added focused tests to verify get_or_create_path behavior for both temporary directories and file parent creation scenarios

Testing
python -m pytest tests/misc/test_file_utils.py -q

[TianqiTang1117]

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[SunsetWolf]

Hi, @TianqiTang1117
Thanks for your interest and contribution to qlib, please fix CI.

[Abhijais4896]

from typing import Dict, Tuple, Union, Callable, List
from typing import Dict, Tuple, Callable, List
import bisect

import numpy as np
import pandas as pd

def concat(data_list: Union[SingleData], axis=0) -> MultiData:
"""concat all SingleData by index.
def concat(data_list: List["SingleData"], axis=0) -> "MultiData":
"""Concat multiple :class:SingleData objects by index.
TODO: now just for SingleData.

Parameters