New Features
- Introduce `openfisca_core.variables.typing`
- Documents the signature of formulas
- Note: as formulas are generated dynamically, documenting them is tricky
Bug Fixes
- Fix the official doc
- Corrects malformed docstrings
- Fix missing and/ou outdated references
Technical Changes
- Add tasks to automatically validate that changes do not break the documentation
Documentation
- Add steps to follow in case the documentation is broken
- Add general documenting guidelines in CONTRIBUTING.md