DOCSP-35011: Add ConnectionId changes link to What's New (#517)

* DOCSP-35011: Add ConnectionId changes link to What's New

* RR feedback

Author: norareidy

source/whats-new.txt

@@ -75,6 +75,9 @@ The 5.0 driver release introduces the following features:
   This relates to a :ref:`breaking change about Observables in this version
   <java-breaking-changes-v5.0-observables>`.
 
+- Changes to the ``ConnectionId`` class. To learn more, see the
+  :ref:`Version 5.0 Breaking Changes <java-breaking-changes-v5.0>`.
+
 .. _version-4.11:
 
 What's New in 4.11