message: Fix a typo in the tutorial
diff: @@ -15,7 +15,7 @@ As always, we would be happy to hear your comments and receive your contribution
  - @subpage tutorial_table_of_content_core
  Here you will learn
  - the about the basic building blocks of this library. A must read for understanding how
  + about the basic building blocks of this library. A must read for understanding how
  to manipulate the images on a pixel level.
  - @subpage tutorial_table_of_content_imgproc
  