Go through the entire repo and solved spelling mistakes

I figured out that there are a few spelling mistakes remaining in different parts of this repo. It happened because of fast typing. So, if anyone is new to Python or wants to revise the basics, then they can help me solve the spelling mistakes in the code comments when they are going through each and every file. It will be really helpful.

Review the entire repository file by file, focusing on the code comments mentioned in the issue. No specific files, tests, or entry points are named, so begin by locating comments with spelling mistakes; done means correcting the spelling mistakes throughout the repository.

由索引模型根据 Issue 内容生成。