docs: update CHANGELOG

Author: Davidyz

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Use character-wised diff instead of byte-wise diff in the LSP server so that it can handle multi-byte characters ([#1042](https://github.com/JohnnyMorganz/StyLua/issues/1042), [#1043](https://github.com/JohnnyMorganz/StyLua/issues/1043)).
+
 ## [2.3.0] - 2025-09-27
 
 ### Added