update changelog

Author: CoolSpy3

docs/reference/changelog-r2025.md

@@ -1,6 +1,8 @@
 # Webots R2025 Change Log
 
 ## Webots R2025b
+  - Enhancements
+    - Added implementations of `wbu_system_tmpdir` and `wbu_system_webots_instance_path` to the MATLAB API ([#6756](https://github.com/cyberbotics/webots/pull/6756)).b
   - Bug Fixes
     - Fixed a bug preventing the `webots-controller` executable from running on arm-based mac devices ([#6806](https://github.com/cyberbotics/webots/pull/6806)).
     - Fixed a bug causing Webots to crash when multiple sounds were used with a [Speaker](speaker.md) node ([#6843](https://github.com/cyberbotics/webots/pull/6843)).