devel/reflection-cpp: add port: C++ static reflection support library

This is a C++ static reflection library.

Goals:

• Trivial to integrate into existing codebases (no code generation, no macros, no build system changes)
• Minimal to zero runtime overhead
• Works with C++20 and later
• Prepared to integrate C++26 reflections when they are available

WWW: https://github.com/contour-terminal/reflection-cpp