Add missing newline

Author: JoshRosen

sql/core/src/main/scala/org/apache/spark/sql/execution/UnsafeRowSerializer.scala

@@ -139,4 +139,4 @@ private class UnsafeRowSerializerInstance(numFields: Int) extends SerializerInst
     throw new UnsupportedOperationException
   override def deserialize[T: ClassTag](bytes: ByteBuffer, loader: ClassLoader): T =
     throw new UnsupportedOperationException
-}
+}