Add assertIterableEquals overflow fix

Issue #2157

Author: sormuras

documentation/src/docs/asciidoc/release-notes/release-notes-5.6.0.adoc

@@ -43,6 +43,8 @@ milestone pages in the JUnit repository on GitHub.
   handles events from multiple levels of nested classes.
 * Module `org.junit.platform.launcher` now reads `java.logging` due to usage of types in
   package `java.util.logging`.
+* Method `assertIterableEquals()` in `Assertions` no longer throws a `StackOverflowError`
+  when comparing iterables with components that themselves implement `Iterable`.
 
 ==== Deprecations and Breaking Changes