[SPARK-10669] [DOCS] Link to each language's API in codetabs in ML docs: spark.mllib

In the Markdown docs for the spark.mllib Programming Guide, we have code examples with codetabs for each language. We should link to each language's API docs within the corresponding codetab, but we are inconsistent about this. For an example of what we want to do, see the "ChiSqSelector" section in https://github.com/apache/spark/blob/64743870f23bffb8d96dcc8a0181c1452782a151/docs/mllib-feature-extraction.md
This JIRA is just for spark.mllib, not spark.ml.

Please let me know if more work is needed, thanks a lot.

Author: Xin Ren <iamshrek@126.com>

Closes #8977 from keypointt/SPARK-10669.

1 files changed, 16 insertions, 6 deletions

diff --git a/docs/mllib-decision-tree.md b/docs/mllib-decision-tree.md
index c1d0f8a6b1..f31c4f8893 100644
--- a/docs/mllib-decision-tree.md
+++ b/docs/mllib-decision-tree.md
@@ -191,7 +191,9 @@ maximum tree depth of 5. The test error is calculated to measure the algorithm a
 
 <div class="codetabs">
 
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`DecisionTree` Scala docs](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree) and [`DecisionTreeModel` Scala docs](api/scala/index.html#org.apache.spark.mllib.tree.model.DecisionTreeModel) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.mllib.tree.DecisionTree
 import org.apache.spark.mllib.tree.model.DecisionTreeModel
@@ -229,7 +231,9 @@ val sameModel = DecisionTreeModel.load(sc, "myModelPath")
 {% endhighlight %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
+Refer to the [`DecisionTree` Java docs](api/java/org/apache/spark/mllib/tree/DecisionTree.html) and [`DecisionTreeModel` Java docs](api/java/org/apache/spark/mllib/tree/model/DecisionTreeModel.html) for details on the API.
+
 {% highlight java %}
 import java.util.HashMap;
 import scala.Tuple2;
@@ -291,7 +295,8 @@ DecisionTreeModel sameModel = DecisionTreeModel.load(sc.sc(), "myModelPath");
 {% endhighlight %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`DecisionTree` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.tree.DecisionTree) and [`DecisionTreeModel` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.tree.DecisionTreeModel) for more details on the API.
 
 {% highlight python %}
 from pyspark.mllib.regression import LabeledPoint
@@ -335,7 +340,9 @@ depth of 5. The Mean Squared Error (MSE) is computed at the end to evaluate
 
 <div class="codetabs">
 
-<div data-lang="scala">
+<div data-lang="scala" markdown="1">
+Refer to the [`DecisionTree` Scala docs](api/scala/index.html#org.apache.spark.mllib.tree.DecisionTree) and [`DecisionTreeModel` Scala docs](api/scala/index.html#org.apache.spark.mllib.tree.model.DecisionTreeModel) for details on the API.
+
 {% highlight scala %}
 import org.apache.spark.mllib.tree.DecisionTree
 import org.apache.spark.mllib.tree.model.DecisionTreeModel
@@ -372,7 +379,9 @@ val sameModel = DecisionTreeModel.load(sc, "myModelPath")
 {% endhighlight %}
 </div>
 
-<div data-lang="java">
+<div data-lang="java" markdown="1">
+Refer to the [`DecisionTree` Java docs](api/java/org/apache/spark/mllib/tree/DecisionTree.html) and [`DecisionTreeModel` Java docs](api/java/org/apache/spark/mllib/tree/model/DecisionTreeModel.html) for details on the API.
+
 {% highlight java %}
 import java.util.HashMap;
 import scala.Tuple2;
@@ -440,7 +449,8 @@ DecisionTreeModel sameModel = DecisionTreeModel.load(sc.sc(), "myModelPath");
 {% endhighlight %}
 </div>
 
-<div data-lang="python">
+<div data-lang="python" markdown="1">
+Refer to the [`DecisionTree` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.tree.DecisionTree) and [`DecisionTreeModel` Python docs](api/python/pyspark.mllib.html#pyspark.mllib.tree.DecisionTreeModel) for more details on the API.
 
 {% highlight python %}
 from pyspark.mllib.regression import LabeledPoint