Edit changelog entry.

Author: finnbear

CHANGELOG.md

@@ -9,11 +9,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Add `Clone` and `PartialEq` implementations to `HistoryBuffer`.
+
 ### Changed
 
 - [breaking-change] `IndexMap` and `IndexSet` now require that keys implement the `core::hash::Hash`
   trait instead of the `hash32::Hash` (v0.2.0) trait
-- `HistoryBuffer` implements `Clone` and `PartialEq`.
 
 ### Fixed