[SPARK-20477][SPARKR][DOC] Document R bisecting k-means in R programming guide

## What changes were proposed in this pull request?

Add hyper link in the SparkR programming guide.

## How was this patch tested?

Build doc and manually check the doc link.

Author: wangmiao1981 <wm624@hotmail.com>

Closes #17805 from wangmiao1981/doc.

docs/sparkr.md

@@ -497,6 +497,7 @@ SparkR supports the following machine learning algorithms currently:
 
 #### Clustering
 
+* [`spark.bisectingKmeans`](api/R/spark.bisectingKmeans.html): [`Bisecting k-means`](ml-clustering.html#bisecting-k-means)
 * [`spark.gaussianMixture`](api/R/spark.gaussianMixture.html): [`Gaussian Mixture Model (GMM)`](ml-clustering.html#gaussian-mixture-model-gmm)
 * [`spark.kmeans`](api/R/spark.kmeans.html): [`K-Means`](ml-clustering.html#k-means)
 * [`spark.lda`](api/R/spark.lda.html): [`Latent Dirichlet Allocation (LDA)`](ml-clustering.html#latent-dirichlet-allocation-lda)