changelog update

Author: michalsn

user_guide_src/source/changelogs/v4.5.6.rst

@@ -30,6 +30,8 @@ Deprecations
 Bugs Fixed
 **********
 
+- **Validation:** Fixed a bug where complex language strings were not properly handled.
+
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_
 for a complete list of bugs fixed.