Merge duplicate UI and Text release notes sections

PiperOrigin-RevId: 362079362

RELEASENOTES.md

@@ -48,7 +48,6 @@
 *   Text
 *   Text
     *   Parse SSA/ASS bold & italic info in `Style:` lines
     *   Parse SSA/ASS bold & italic info in `Style:` lines
         ([#8435](https://github.com/google/ExoPlayer/issues/8435)).
         ([#8435](https://github.com/google/ExoPlayer/issues/8435)).
-*   Text:
     *   Don't display subtitles after the end position of the current media
     *   Don't display subtitles after the end position of the current media
         period (if known). This ensures sideloaded subtitles respect the end
         period (if known). This ensures sideloaded subtitles respect the end
         point of `ClippingMediaPeriod` and prevents content subtitles from
         point of `ClippingMediaPeriod` and prevents content subtitles from