fixed a typing error

library/src/main/java/com/google/android/exoplayer2/trackselection/BaseTrackSelection.java

@@ -148,7 +148,7 @@ public abstract class BaseTrackSelection implements TrackSelection {
   }
 
   /**
-   * Returns whether the track at the specified index in the selection is blaclisted.
+   * Returns whether the track at the specified index in the selection is blacklisted.
    *
    * @param index The index of the track in the selection.
    * @param nowMs The current time in the timebase of {@link SystemClock#elapsedRealtime()}.