Update docstrings and type hints for Index and IndexAsyncio

[jhamon]

Improve Index and IndexAsyncio classes: code quality and consistency

Summary

Improvements to the Index and IndexAsyncio classes for code quality, type safety, error handling, and documentation. Changes are non-breaking and maintain backward compatibility.

Changes Made

1. Fixed Mutable Default Argument

• Files: pinecone/db_data/index.py, pinecone/db_data/index_asyncio.py
• Changed additional_headers: Optional[Dict[str, str]] = {} to = None with initialization inside the method
• Prevents shared mutable state issues

2. Fixed Outdated Comment

• File: pinecone/db_data/index.py
• Updated comment from "ImportFeatureMixin" to "PluginAware" to accurately reflect the parent class

3. Added Missing Documentation

• Files: pinecone/db_data/index.py, pinecone/db_data/index_asyncio.py
• Added RST-formatted docstring to upsert_records method with Args, Examples, and usage details

4. Added Validation Decorator

• Files: pinecone/db_data/index.py, pinecone/db_data/index_asyncio.py
• Added @validate_and_convert_errors decorator to upsert_records method for consistent error handling

5. Improved Type Hints

• Files: pinecone/db_data/index.py, pinecone/db_data/index_asyncio.py
• Changed records: List[Dict] to List[Dict[str, Any]] in upsert_records method for better type safety

6. Improved Exception Handling

• Files: pinecone/db_data/index.py, pinecone/db_data/index_asyncio.py
• Replaced generic raise Exception(...) with raise ValueError(...) in search methods for more appropriate exception types

Testing

• ✅ No linting errors
• ✅ Code compiles successfully
• ✅ All changes maintain backward compatibility

Impact

• Code Quality: Fixes mutable default argument anti-pattern
• Type Safety: More specific type hints improve IDE support and type checking
• Documentation: Complete API documentation for upsert_records method
• Consistency: Both sync and async implementations now aligned
• Error Handling: Consistent use of @validate_and_convert_errors decorator and appropriate exception types

Files Changed

• pinecone/db_data/index.py
• pinecone/db_data/index_asyncio.py