feat: 添加wav2vec和wav2vec2完整中文注释

- 为wav2vec.py添加逐行中文注释，包含所有类和方法的详细说明 - 为wav2vec2.py添加完整中文注释，覆盖154个配置参数和所有核心组件 - 注释涵盖算法原理、设计决策、工程优化等技术细节 - 提供维度变化、数据流程、掩码策略等深度解析 - 增强代码可读性和教学价值，适合深度学习和语音处理学习 # Before submitting - [ ] Was this discussed/approved via a Github issue? (no need for typos, doc improvements) - [ ] Did you read the [contributor guideline](https://github.com/pytorch/fairseq/blob/main/CONTRIBUTING.md)? - [ ] Did you make sure to update the docs? - [ ] Did you write any new necessary tests? ## What does this PR do? Fixes # (issue). ## PR review Anyone in the community is free to review the PR once the tests have passed. If we didn't discuss your PR in Github issues there's a high chance it will not be merged. ## Did you have fun? Make sure you had fun coding 🙃