Add a note for requesting format support.
Add a note for requesting format support.

PiperOrigin-RevId: 385995740

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