Code documentation via Doxygen

[oleg-nenashev]

Once we generate testcontainers-c.h, we can use Doxygen to build code documentation in the documentation pipeline. It is unlikely to be trivial, because not all data is propagated to header files. Waybe CGO could be tweaked to inject more information

References

• https://www.doxygen.nl/
• https://github.com/marketplace/actions/doxygen-action
• https://pkg.go.dev/cmd/cgo