update tutorial link for dnn

doc/tutorials/dnn/table_of_content_dnn.markdown

+Deep Neural Networks (dnn module) {#tutorial_table_of_content_dnn}
+=====================================
+
+-   @subpage tutorial_dnn_googlenet
+
+    *Compatibility:* \> OpenCV 3.3
+
+    *Author:* Vitaliy Lyudvichenko
+
+    In this tutorial you will learn how to use opencv_dnn module for image classification by using GoogLeNet trained network from Caffe model zoo.
+
+-   @subpage tutorial_dnn_halide
+
+    *Compatibility:* \> OpenCV 3.3
+
+    *Author:* Dmitry Kurtaev
+
+    This tutorial guidelines how to run your models in OpenCV deep learning module using Halide language backend
+
+-   @subpage tutorial_dnn_halide_scheduling
+
+    *Compatibility:* \> OpenCV 3.3
+
+    *Author:* Dmitry Kurtaev
+
+    In this tutorial we describe the ways to schedule your networks using Halide backend in OpenCV deep learning module.
\ No newline at end of file

doc/tutorials/tutorials.markdown

@@ -85,3 +85,7 @@ As always, we would be happy to hear your comments and receive your contribution
 -   @subpage tutorial_table_of_content_viz
 
     These tutorials show how to use Viz module effectively.
+
+-   @subpage tutorial_table_of_content_dnn
+
+    These tutorials show how to use dnn module effectively.