Doc fix

Author: yjshen

sql/hive/compatibility/src/test/scala/org/apache/spark/sql/hive/execution/HiveCompatibilitySuite.scala

@@ -933,7 +933,7 @@ class HiveCompatibilitySuite extends HiveQueryFileTest with BeforeAndAfter {
     "udf_stddev_pop",
     "udf_stddev_samp",
     "udf_string",
-    "udf_struct",  // TODO: FIX THIS and enable it.
+    "udf_struct",
     "udf_substring",
     "udf_subtract",
     "udf_sum",