[eclipse-iceoryx#491] Add release notes

doc/release-notes/iceoryx2-unreleased.md

@@ -16,6 +16,7 @@
 * Developer permissions for resources [#460](https://github.com/eclipse-iceoryx/iceoryx2/issues/460)
 * Add `--send-copy` flag to Benchmark to consider mem operations [#483](https://github.com/eclipse-iceoryx/iceoryx2/issues/483)
 * Support for slices in the C++ bindings [#490](https://github.com/eclipse-iceoryx/iceoryx2/issues/490)
+* Add API to retrieve string description of error enums [$491](https://github.com/eclipse-iceoryx/iceoryx2/issues/491)
 
 ### Bugfixes
 
@@ -58,10 +59,13 @@
     conflicts when merging.
 -->
 
-* APIs to support slices in the C++ bindings [#490](https://github.com/eclipse-iceoryx/iceoryx2/issues/490)
+* APIs to support slices in the C/C++ bindings [#490](https://github.com/eclipse-iceoryx/iceoryx2/issues/490)
 * Rename `iox2_publisher_loan` to `iox2_publisher_loan_slice_uninit` [#490](https://github.com/eclipse-iceoryx/iceoryx2/issues/490)
     1. C always loans slices, for a single element, specify the
        `number_of_elements` to be 1
+* Add APIs to C/C++ bindings to get string representation of error enum
+    1. C API: `iox2_{error_enum_name}_string()`
+    2. C++ API: `error_string(ErrorEnum)`
 
 ### API Breaking Changes