doc: release: mention new video-sw-generator snippet

This snippet got introduced, and is not a breaking change for C APIs but
still introduce a change of command line to use for building projects,
so add a migration guide entry.

Signed-off-by: Josuah Demangeon <me@josuah.net>

Author: josuah

doc/releases/migration-guide-4.2.rst

@@ -608,6 +608,9 @@ Video
   ``video_stream_start``
   ``video_stream_stop``
 
+* Samples and projects using the :zephyr:board:`native_sim` now require specifying the
+  ``--snippet`` :ref:`video-sw-generator <snippet-video-sw-generator>` to build correctly.
+
 Audio
 =====
 

doc/releases/release-notes-4.2.rst

@@ -248,6 +248,7 @@ New APIs and options
   * :c:func:`video_api_ctrl_t`
   * :c:func:`video_query_ctrl`
   * :c:func:`video_print_ctrl`
+  * :ref:`video-sw-generator <snippet-video-sw-generator>`
 
 * PCIe