fix some typo in doc/comments

[qianyun210603]

Description

Fix some typo in doc/comments.
Resolve some lint warning.

Motivation and Context

improve code quality

How Has This Been Tested?

• Pass the test by running: pytest qlib/tests/test_all_pipeline.py under upper directory of qlib.
• If you are adding a new feature, test on your own test scripts.

Screenshots of Test Results (if appropriate):

1. Pipeline test:
2. Your own tests:

Types of changes

• Fix bugs
• Add new feature
• Update documentation

[you-n-g]

Thanks for your contribution.
Please fix the CI error.

[qianyun210603]

Thanks for your contribution. Please fix the CI error.

A quick question please.
Why my black forces spaces before and after operator **

but the qlib CI forces no spaces? Do you have any clue that how my black should be configured to be consistent with CI? Or it's version inconsistency?

Thanks!

[you-n-g]

@qianyun210603 I think this is a problem with the black version.
You can pip install -U black to upgrade your black to check if it works.

[you-n-g]

It looks great now.
Thanks