doc: releases: mention the video selection API functions

Add a mention to the video_set_selection() and video_get_selection()
introduced in #91878.

Signed-off-by: Josuah Demangeon <[email protected]>

Author: josuah

doc/releases/release-notes-4.2.rst

@@ -294,6 +294,8 @@ New APIs and options
   * :c:func:`video_api_ctrl_t`
   * :c:func:`video_query_ctrl`
   * :c:func:`video_print_ctrl`
+  * :c:func:`video_set_selection`
+  * :c:func:`video_get_selection`
   * :ref:`video-sw-generator <snippet-video-sw-generator>`
 
 * PCIe