The Solidity programming language supports the usage of inline documentation which is a special form of code comments to explain the intent of a given Smart Contract functionality. Using this is especially helpful when working on larger projects with a (potential) larger team of engineers.
The "Solidity Docgen" tool uses such comments to auto-generate a self-contained documentation for the project in question. Simply run one command to get the content for your projects docs website or the onboarding guide for your teammates.
- OpenZeppelin