Fixed typo

Author: akarnokd

src/main/java/rx/internal/schedulers/NewThreadWorker.java

@@ -155,8 +155,8 @@ public Subscription schedule(final Action0 action, long delayTime, TimeUnit unit
     }
 
     /**
-     * Perform sthe actual scheduling of a potentially delayed task and assigns the
-     * future to the ScheduledAction returned.
+     * Performs the actual scheduling of a potentially delayed task and assigns the
+     * future to the ScheduledAction it returs.
      * @param action the action to schedule
      * @param delayTime the scheduling delay if positive
      * @param unit the scheduling delay's time unit