update svg to have a white background for better display in dark mode

topics/statistics/tutorials/clustering_machinelearning/tutorial.md

@@ -117,7 +117,7 @@ All data points are chosen at the bottom and each one is assigned to a separate
 
 By looking at the dendrogram, the clusters can be observed showing different groups in the best way. The optimal number of clusters is the number of vertical lines in the dendrogram cut by a horizontal line that can transverse maximum distance vertically without intersecting a cluster.
 
-In the above example, the best choice of the number of clusters will be 4 as the red horizontal line in the dendrogram below covers maximum vertical distance AB. For more details, please read [here](https://www.analyticsvidhya.com/blog/2016/11/an-introduction-to-clustering-and-different-methods-of-clustering/).
+In the above example, the best choice of the number of clusters will be 4 as the red horizontal line in the dendrogram below covers maximum vertical distance AB. For more details, please read [this blogpost entitled *"Clustering | Introduction, Different Methods, and Applications"*](https://www.analyticsvidhya.com/blog/2016/11/an-introduction-to-clustering-and-different-methods-of-clustering/).
 ![data](images/Hierarchical_clustering_2.png "Hierarchical clustering")