Add module docstrings to utils folder files

[dosine-staging]

This pull request adds descriptive docstrings to each file in the tortoise/utils folder. Each docstring provides a brief overview of the module's purpose and functionality, enhancing code readability and maintainability. The changes include:

• audio.py: Added a docstring explaining utility functions for handling audio data.
• device.py: Added a docstring for managing device settings and memory usage in PyTorch.
• diffusion.py: Added a docstring for implementations of diffusion models and related utilities.
• stft.py: Added a docstring for the Short-Time Fourier Transform implementation using PyTorch.
• text.py: Added a docstring for text processing tasks and normalization utilities.
• tokenizer.py: Added a docstring for tokenization and text normalization using BPE.
• torch_intermediary.py: Added a docstring for managing conditional imports for performance optimization.
• typical_sampling.py: Added a docstring for the TypicalLogitsWarper class and its sampling strategies.
• wav2vec_alignment.py: Added a docstring for aligning audio with expected text using Wav2Vec2 models.

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Created by Genie. You can follow its reasoning on Cosine