[HOT-FIX] Fix style.

https://github.com/apache/spark/pull/8882 broke our build.

Author: Yin Huai <yhuai@databricks.com>

Closes #8964 from yhuai/fixStyle.

mllib/src/main/scala/org/apache/spark/ml/tuning/CrossValidator.scala

@@ -138,8 +138,8 @@ class CrossValidator(override val uid: String) extends Estimator[CrossValidatorM
  * Model from k-fold cross validation.
  *
  * @param bestModel The best model selected from k-fold cross validation.
- * @param avgMetrics Average cross-validation metrics for each paramMap in [[estimatorParamMaps]], in the
- *                   corresponding order.
+ * @param avgMetrics Average cross-validation metrics for each paramMap in
+ *                   [[estimatorParamMaps]], in the corresponding order.
  */
 @Experimental
 class CrossValidatorModel private[ml] (