docs: update changelog

Signed-off-by: Rob Ede <[email protected]>

Author: robjtede

CHANGELOG.md

@@ -8,10 +8,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0),
 
 ## [0.4.21](https://github.com/Nullus157/async-compression/compare/v0.4.20...v0.4.21) - 2025-03-15
 
-### Other
+### Fixed
 
-- fix flate encoder: do not mark internal state as flushed if it ran out of buffer space
-- Add assertion in `produce` method to check buffer capacity in implementations for `BufWriter`
+- When flate encoding, do not mark internal state as flushed if it ran out of buffer space.
+- Add debug assertion in `produce` method to check buffer capacity in implementations for `BufWriter`.
 
 ## [0.4.20](https://github.com/Nullus157/async-compression/compare/v0.4.19...v0.4.20) - 2025-02-28