docs: v3.5.0 changelog

Author: kozistr

docs/changelogs/v3.5.0.md

@@ -9,6 +9,7 @@
     * [Improving Training Stability for Large Language Model Pretraining](https://arxiv.org/abs/2502.11034)
 * Implement `Simplified-Ademamix` optimizer. (#364, #366)
     * [Connections between Schedule-Free Optimizers, AdEMAMix, and Accelerated SGD Variants](https://arxiv.org/abs/2502.02431)
+* Support `Ackley` function for testing optimization algorithms.
 
 ### Update