Tidy up the CHANGELOG a bit.

Author: asomers

CHANGELOG.md

@@ -4,23 +4,15 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [Unreleased] - ReleaseDate
-### Added
-### Changed
 ### Fixed
 - Fix `SockaddrIn6` bug that was swapping flowinfo and scope_id byte ordering.
   ([#1964](https://github.com/nix-rust/nix/pull/1964))
 
-### Removed
-
 ## [0.26.1] - 2022-11-29
-### Added
-### Changed
 ### Fixed
 - Fix UB with `sys::socket::sockopt::SockType` using `SOCK_PACKET`.
   ([#1821](https://github.com/nix-rust/nix/pull/1821))
 
-### Removed
-
 ## [0.26.0] - 2022-11-29
 ### Added