Add release notes for Reader UI navigation changes

Author: wargcm

RELEASE-NOTES.txt

@@ -3,6 +3,7 @@
 * [**] Prevent images from temporarily disappearing when uploading media [https://github.com/WordPress/gutenberg/pull/57869]
 * [**] Fix crash occurring on large post on Android [https://github.com/WordPress/gutenberg/pull/58266]
 * [*] [Jetpack-only] Site Monitoring: Add Metrics, PHP Logs, and Web Server Logs under Site Monitoring [#22475, #22499, #22504, #22500]
+* [***] [Jetpack-only] Reader: introduced new UI/UX for content navigation and filtering [#]
 
 24.0.1
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