Fix release notes Markdown syntax

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Created by MOE: https:/google/moe
MOE_MIGRATED_REVID=215868785

RELEASENOTES.md

@@ -348,18 +348,18 @@
  begins, and poll the audio timestamp less frequently once it starts
  advancing ([#3841](https:/google/ExoPlayer/issues/3841)).
  * Add an option to skip silent audio in `PlaybackParameters`
- ((#2635)[https:/google/ExoPlayer/issues/2635]).
+ ([#2635](https:/google/ExoPlayer/issues/2635)).
  * Fix an issue where playback of TrueHD streams would get stuck after seeking
  due to not finding a syncframe
- ((#3845)[https:/google/ExoPlayer/issues/3845]).
+ ([#3845](https:/google/ExoPlayer/issues/3845)).
  * Fix an issue with eac3-joc playback where a codec would fail to configure
- ((#4165)[https:/google/ExoPlayer/issues/4165]).
+ ([#4165](https:/google/ExoPlayer/issues/4165)).
  * Handle non-empty end-of-stream buffers, to fix gapless playback of streams
  with encoder padding when the decoder returns a non-empty final buffer.
  * Allow trimming more than one sample when applying an elst audio edit via
  gapless playback info.
  * Allow overriding skipping/scaling with custom `AudioProcessor`s
- ((#3142)[https:/google/ExoPlayer/issues/3142]).
+ ([#3142](https:/google/ExoPlayer/issues/3142)).
 * Caching:
  * Add release method to the `Cache` interface, and prevent multiple instances
  of `SimpleCache` using the same folder at the same time.