Fix miscellaneous documentation typos and grammatical errors

[buildwithsuhana]

Description of the change

This PR corrects several minor typos and grammatical errors found in docstrings, comments, and documentation across the repository to improve clarity and professional quality.

Summary of changes:

• Duplicate words: Fixed instances of "and and" and "to to" in box_matcher.py, segformer_image_segmenter.py, and STYLE_GUIDE.md.
• Article usage ("a" vs "an"): Corrected grammar for terms starting with vowel sounds (e.g., "an array", "an int", "an obscure bug") in sentence_piece_tokenizer.py, byte_pair_tokenizer.py, cached_multi_head_attention.py, and rotary_embedding.py.

Checklist

• I have added all the necessary unit tests for my change.
• I have verified that my change does not break existing code and works with all backends (TensorFlow, JAX, and PyTorch).
• My PR is based on the latest changes of the main branch (if unsure, rebase the code).
• I have followed the Keras Hub Model contribution guidelines in making these changes.
• I have followed the Keras Hub API design guidelines in making these changes.
• I have signed the Contributor License Agreement.

[gemini-code-assist]

Code Review

This pull request corrects several minor grammatical errors and typos across various files, including fixing duplicate words (such as 'to to' and 'and and') and correcting indefinite articles (such as 'a int' to 'an int', 'a obscure' to 'an obscure', and 'a array' to 'an array') in docstrings and comments. There are no review comments, and we have no additional feedback to provide.