Remove an invalid non ASCII encoded char from comment of LearnerSyncThrottler.

The char is non ASCII encoded (so potentially it could break builds where encoding was not set as UTF8), and it is clearly redudant (as semantically
there should be no chars between 'or' and 'from', in this case.

Remove the char fixes both.

zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/LearnerSyncThrottler.java

@@ -23,7 +23,7 @@ import org.slf4j.LoggerFactory;
 
 /**
  * Utility class to limit the number of concurrent syncs from a leader to
- * observers and followers orß from a follower to observers.  {@link LearnerHandler}
+ * observers and followers or from a follower to observers.  {@link LearnerHandler}
  * objects should call {@link #beginSync(boolean)} before sending a sync and
  * {@link #endSync()} after finishing, successfully or not.
  *