[SPARK-14340][EXAMPLE][DOC] Update Examples and User Guide for ml.BisectingKMeans

## What changes were proposed in this pull request?

1, add BisectingKMeans to ml-clustering.md
2, add the missing Scala BisectingKMeansExample
3, create a new datafile `data/mllib/sample_kmeans_data.txt`

## How was this patch tested?

manual tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #11844 from zhengruifeng/doc_bkm.

1 files changed, 36 insertions, 1 deletions

diff --git a/docs/ml-clustering.md b/docs/ml-clustering.md
index 440c455cd0..1245b8bbc8 100644
--- a/docs/ml-clustering.md
+++ b/docs/ml-clustering.md
@@ -104,4 +104,39 @@ Refer to the [Java API docs](api/java/org/apache/spark/ml/clustering/LDA.html) f
 {% include_example java/org/apache/spark/examples/ml/JavaLDAExample.java %}
 </div>
 
-</div>
\ No newline at end of file
+</div>
+
+## Bisecting k-means
+
+
+Bisecting k-means is a kind of [hierarchical clustering](https://en.wikipedia.org/wiki/Hierarchical_clustering) using a
+divisive (or "top-down") approach: all observations start in one cluster, and splits are performed recursively as one
+moves down the hierarchy.
+
+Bisecting K-means can often be much faster than regular K-means, but it will generally produce a different clustering.
+
+`BisectingKMeans` is implemented as an `Estimator` and generates a `BisectingKMeansModel` as the base model.
+
+### Example
+
+<div class="codetabs">
+
+<div data-lang="scala" markdown="1">
+Refer to the [Scala API docs](api/scala/index.html#org.apache.spark.ml.clustering.BisectingKMeans) for more details.
+
+{% include_example scala/org/apache/spark/examples/ml/BisectingKMeansExample.scala %}
+</div>
+
+<div data-lang="java" markdown="1">
+Refer to the [Java API docs](api/java/org/apache/spark/ml/clustering/BisectingKMeans.html) for more details.
+
+{% include_example java/org/apache/spark/examples/ml/JavaBisectingKMeansExample.java %}
+</div>
+
+<div data-lang="python" markdown="1">
+Refer to the [Python API docs](api/python/pyspark.ml.html#pyspark.ml.clustering.BisectingKMeans) for more details.
+
+{% include_example python/ml/bisecting_k_means_example.py %}
+</div>
+
+</div>