Include all code required for compilation in the PyPI source code .tar.gz

[apcamargo]

I'm working on a recipe to add tree-sitter-sql to [conda-forge](https://conda-forge.org/), but I can't compile it from the source code downloaded from PyPI because some necessary files (e.g., the tree-sitter headers) are missing.

Since PyPI's source distribution is used when a wheel is unavailable for a given architecture, it would be beneficial to include all required files in the .tar.gz archive. This would make it possible to compile the library directly and facilitate adding tree-sitter-sql to conda-forge.