* Fix bad link in docs. PR [#1603](https://github.com/tiangolo/fastapi/pull/1603) by [@molto0504](https://github.com/molto0504).
* Add Vim temporary files to `.gitignore` for contributors using Vim. PR [#1590](https://github.com/tiangolo/fastapi/pull/1590) by [@asheux](https://github.com/asheux).
* Fix typo in docs for sub-applications. PR [#1578](https://github.com/tiangolo/fastapi/pull/1578) by [@schlpbch](https://github.com/schlpbch).
* Use `Optional` in all the examples in the docs. Original PR [#1574](https://github.com/tiangolo/fastapi/pull/1574) by [@chrisngyn](https://github.com/chrisngyn), [@kx-chen](https://github.com/kx-chen), [@YKo20010](https://github.com/YKo20010). Updated and merged PR [#1644](https://github.com/tiangolo/fastapi/pull/1644).