text.nix flake-parts module

The option text.<name> supports either a string or a submodule with attributes order and parts. The parts attribute can either be a string, which will get concatenated in the order laid out in text.<name>.order, or can itself have the attributes order and parts, in which case it will be evaluated recursively.''

Acknowledgements

Full credits go to @mightyiam for coming up with the original implementation. I simply added the recursive parts and headings.