Merge pull request #15345 from prakhar9998:patch-1

* fix broken code link

resolves  #15344

* Update stitcher.markdown

* update 3.4 link

doc/tutorials/stitching/stitcher/stitcher.markdown

@@ -15,7 +15,7 @@ Code
 ----
 
 This tutorial code's is shown lines below. You can also download it from
-[here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/samples/cpp/stitching.cpp).
+[here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/stitching.cpp).
 
 @include samples/cpp/stitching.cpp