Updates CHANGELOG by describing new AI powered actions on a branch

(#4443, #4522)

Author: sergeibbb

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 
 ## [Unreleased]
 
+### Added
+
+- Adds AI powered operations for a branch: "Explain Unpushed Changed". They are added to the _Commit Graph_ and views context menu for branches ([#4443](https://github.com/gitkraken/vscode-gitlens/issues/4443))
+
 ## [17.6.0] - 2025-10-07
 
 ### Added