doc: migration-guide: Add a link to the release notes

Add a link to the 3.5 release notes from the migration guide.

Signed-off-by: Johan Hedberg <[email protected]>

Author: Johan Hedberg

doc/releases/migration-guide-3.5.rst

@@ -8,6 +8,9 @@ Migration guide to Zephyr v3.5.0 (Working Draft)
 This document describes the changes required or recommended when migrating your
 application from Zephyr v3.4.0 to Zephyr v3.5.0.
 
+Any other changes (not directly related to migrating applications) can be found in
+the :ref:`release notes<zephyr_3.5>`.
+
 Required changes
 ****************