[SPARK-19410][DOC] Fix brokens links in ml-pipeline and ml-tuning

## What changes were proposed in this pull request?
Fix brokens links in ml-pipeline and ml-tuning
`<div data-lang="scala">`  ->   `<div data-lang="scala" markdown="1">`

## How was this patch tested?
manual tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #16754 from zhengruifeng/doc_api_fix.

1 files changed, 4 insertions, 4 deletions

diff --git a/docs/ml-tuning.md b/docs/ml-tuning.md
index a135adc433..e9123db296 100644
--- a/docs/ml-tuning.md
+++ b/docs/ml-tuning.md
@@ -74,21 +74,21 @@ However, it is also a well-established method for choosing parameters which is m
 
 <div class="codetabs">
 
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
 
 Refer to the [`CrossValidator` Scala docs](api/scala/index.html#org.apache.spark.ml.tuning.CrossValidator) for details on the API.
 
 {% include_example scala/org/apache/spark/examples/ml/ModelSelectionViaCrossValidationExample.scala %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
 
 Refer to the [`CrossValidator` Java docs](api/java/org/apache/spark/ml/tuning/CrossValidator.html) for details on the API.
 
 {% include_example java/org/apache/spark/examples/ml/JavaModelSelectionViaCrossValidationExample.java %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
 
 Refer to the [`CrossValidator` Python docs](api/python/pyspark.ml.html#pyspark.ml.tuning.CrossValidator) for more details on the API.
 
@@ -128,7 +128,7 @@ Refer to the [`TrainValidationSplit` Java docs](api/java/org/apache/spark/ml/tun
 {% include_example java/org/apache/spark/examples/ml/JavaModelSelectionViaTrainValidationSplitExample.java %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
 
 Refer to the [`TrainValidationSplit` Python docs](api/python/pyspark.ml.html#pyspark.ml.tuning.TrainValidationSplit) for more details on the API.