1. fix an error in sample code
2. change an external link to maintain consistency with the previous tutorial
remove highlighting in some function links

1. Remove whole-document highlighting in some function links
2. fix the function alias `readwriteimagevideo`
Fixed Load, Modify, and Save an Image tutorial
Keep definitions of link aliases consistent
Removed obsolete list from docs
Merge pull request #2498 from dreamworld:fix_tutorial_mat_the_basic_image_container