Updated sample files documentation inclusions

samples/cpp/tutorial_code/introduction/display_image/display_image.cpp

@@ -1,23 +1,35 @@
+//! [includes]
 #include <opencv2/core/core.hpp>
 #include <opencv2/imgcodecs.hpp>
 #include <opencv2/highgui/highgui.hpp>
 
 #include <iostream>
 #include <string>
+//! [includes]
 
+//! [namespace]
 using namespace cv;
+//! [namespace]
+
 using namespace std;
 
 int main( int argc, char** argv )
 {
+    //! [load]
     string imageName("../data/HappyFish.jpg"); // by default
     if( argc > 1)
     {
         imageName = argv[1];
     }
+    //! [load]
 
+    //! [mat]
     Mat image;
+    //! [mat]
+
+    //! [imread]
     image = imread(imageName.c_str(), IMREAD_COLOR); // Read the file
+    //! [imread]
 
     if( image.empty() )                      // Check for invalid input
     {
@@ -25,9 +37,16 @@ int main( int argc, char** argv )
         return -1;
     }
 
+    //! [window]
     namedWindow( "Display window", WINDOW_AUTOSIZE ); // Create a window for display.
-    imshow( "Display window", image );                // Show our image inside it.
+    //! [window]
 
+    //! [imshow]
+    imshow( "Display window", image );                // Show our image inside it.
+    //! [imshow]
+
+    //! [wait]
     waitKey(0); // Wait for a keystroke in the window
+    //! [wait]
     return 0;
 }