Add pr to the changelog

Author: antonwolfy

CHANGELOG.md

@@ -43,6 +43,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Extended `dpnp.pad` to support `pad_width` keyword as a dictionary [#2535](https://github.com/IntelPython/dpnp/pull/2535)
 * Redesigned `dpnp.erf` function through pybind11 extension of OneMKL call or dedicated kernel in `ufunc` namespace [#2551](https://github.com/IntelPython/dpnp/pull/2551)
 * Improved performance of batched implementation of `dpnp.linalg.det` and `dpnp.linalg.slogdet` [#2572](https://github.com/IntelPython/dpnp/pull/2572)
+* Improved documentations of `dpnp.tril_indices` and `dpnp.triu_indices` to clarify the returned order of indices [#2586](https://github.com/IntelPython/dpnp/pull/2586)
 
 ### Deprecated