[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.

(cherry picked from commit 04ee8cf6)
Signed-off-by: Sean Owen <sowen@cloudera.com>

docs/ml-pipeline.md

@@ -206,7 +206,7 @@ This example covers the concepts of `Estimator`, `Transformer`, and `Param`.
 
 <div class="codetabs">
 
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
 
 Refer to the [`Estimator` Scala docs](api/scala/index.html#org.apache.spark.ml.Estimator),
 the [`Transformer` Scala docs](api/scala/index.html#org.apache.spark.ml.Transformer) and
@@ -215,7 +215,7 @@ the [`Params` Scala docs](api/scala/index.html#org.apache.spark.ml.param.Params)
 {% include_example scala/org/apache/spark/examples/ml/EstimatorTransformerParamExample.scala %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
 
 Refer to the [`Estimator` Java docs](api/java/org/apache/spark/ml/Estimator.html),
 the [`Transformer` Java docs](api/java/org/apache/spark/ml/Transformer.html) and
@@ -224,7 +224,7 @@ the [`Params` Java docs](api/java/org/apache/spark/ml/param/Params.html) for det
 {% include_example java/org/apache/spark/examples/ml/JavaEstimatorTransformerParamExample.java %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
 
 Refer to the [`Estimator` Python docs](api/python/pyspark.ml.html#pyspark.ml.Estimator),
 the [`Transformer` Python docs](api/python/pyspark.ml.html#pyspark.ml.Transformer) and
@@ -241,14 +241,14 @@ This example follows the simple text document `Pipeline` illustrated in the figu
 
 <div class="codetabs">
 
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
 
 Refer to the [`Pipeline` Scala docs](api/scala/index.html#org.apache.spark.ml.Pipeline) for details on the API.
 
 {% include_example scala/org/apache/spark/examples/ml/PipelineExample.scala %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
 
 
 Refer to the [`Pipeline` Java docs](api/java/org/apache/spark/ml/Pipeline.html) for details on the API.
@@ -256,7 +256,7 @@ Refer to the [`Pipeline` Java docs](api/java/org/apache/spark/ml/Pipeline.html)
 {% include_example java/org/apache/spark/examples/ml/JavaPipelineExample.java %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
 
 Refer to the [`Pipeline` Python docs](api/python/pyspark.ml.html#pyspark.ml.Pipeline) for more details on the API.
 

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.