Update dependencies and enhance documentation in Cargo files

- Upgraded several dependencies in Cargo.lock and Cargo.toml, including syn to version 2.0.117 and rand to version 0.10.0, to improve compatibility and functionality.
- Updated text-splitter to version 0.29.0 for enhanced performance.
- Added new feature flags in the documentation for better configuration options, including support for various backends and optimizations.

Author: akshayballal95