Update CHANGELOG.md to more concise description

Co-authored-by: Soso <[email protected]>

Author: 2 people

CHANGELOG.md

@@ -33,7 +33,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - CI now uses flags specified in `Cargo.toml` for `rustdoc` tests.
 - Fixed clippy lints.
-- The `UnionNode<T>` in `pool` now has the correct memory layout for reinterpreting it as a pointer to `T`
+- Fixed the memory layout of the internal `UnionNode<T>` type, fixing possible Undefined Behaviour.
 
 ### Removed