* ♻ Change a `dict()` for `{}` in `fastapi/utils.py`. PR [#3138](https://github.com/tiangolo/fastapi/pull/3138) by [@ShahriyarR](https://github.com/ShahriyarR).
* ♻ Move internal variable for errors in `jsonable_encoder` to put related code closer. PR [#4560](https://github.com/tiangolo/fastapi/pull/4560) by [@GuilleQP](https://github.com/GuilleQP).
* ♻ Simplify conditional assignment in `fastapi/dependencies/utils.py`. PR [#4597](https://github.com/tiangolo/fastapi/pull/4597) by [@cikay](https://github.com/cikay).
* 🎨 Fix syntax highlighting in docs for OpenAPI Callbacks. PR [#4368](https://github.com/tiangolo/fastapi/pull/4368) by [@xncbf](https://github.com/xncbf).