Clean up release notes
Clean up release notes

PiperOrigin-RevId: 251269746

google/ExoPlayer,ened/ExoPlayer,androidx/media,ened/ExoPlayer,amzn/exoplayer-amazon-port,androidx/media,ened/ExoPlayer,stari4ek/ExoPlayer,amzn/exoplayer-amazon-port,google/ExoPlayer,superbderrick/ExoPlayer,androidx/media,superbderrick/ExoPlayer,amzn/exoplayer-amazon-port,stari4ek/ExoPlayer,superbderrick/ExoPlayer,google/ExoPlayer,stari4ek/ExoPlayer