expint_i and expint_n

[jorenham]

No description provided.

[Copilot]

Pull Request Overview

This PR adds support for exponential integral functions by implementing expint_i and expint_n functions that wrap the corresponding Boost Math library functions.

• Adds FFI bindings for math_expint_i and math_expint_n functions
• Implements Rust wrapper functions with proper documentation and test coverage
• Updates module exports to make the new functions publicly available

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
wrapper.cpp	Adds C++ wrapper functions for boost exponential integral functions
src/ffi.rs	Declares FFI bindings for the new exponential integral functions
src/math/special_functions/expint.rs	Implements Rust wrapper functions with documentation and tests
src/math/special_functions/mod.rs	Exports the new expint module
src/math/mod.rs	Updates documentation and re-exports expint functions

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}