fix: changelog as improvement

CHANGELOG.md

@@ -37,13 +37,16 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## Unreleased
 
-### State Machine Breaking
+### Improvements
 
-- [#402](https://github.com/babylonlabs-io/babylon/pull/402) **Babylon multi-staking support**.
-This PR contains a series of PRs on multi-staking support and BTC stakingintegration.
 - [#391](https://github.com/babylonlabs-io/babylon/pull/391) Fix e2e `TestBTCRewardsDistribution` flunky
 check of rewards
 - [#458](https://github.com/babylonlabs-io/babylon/pull/458) Set `CosmosProvider` functions as public
+
+### State Machine Breaking
+
+- [#402](https://github.com/babylonlabs-io/babylon/pull/402) **Babylon multi-staking support**.
+This PR contains a series of PRs on multi-staking support and BTC stakingintegration.
 - [#457](https://github.com/babylonlabs-io/babylon/pull/457) Remove staking msg server and update gentx to generate
 `MsgWrappedCreateValidator`