Fix javadoc error

Change-Id: I4765b8fa77da381451d8b33d6ac3cbba93f7d1f5

@@ -62,7 +62,7 @@ public interface Meter {
     /**
     /**
      * The unit used within this meter.
      * The unit used within this meter.
      *
      *
-     * @return
+     * @return the unit
      */
      */
     Unit unit();
     Unit unit();