Studio accidentally renamed some of the javadoc to reflect the new
vorbis module. Revert it to the dev javadoc, as the ExoPlayer devs
don't update the javadoc until a release.
Also consolidate the threading warning info with the same info on the
hello world page and update the version that the
setThrowsWhenUsingWrongThread() method will be removed in.
PiperOrigin-RevId: 369657759
