This reduces duplicated documentation and fixes two bugs. One minor additional change is that Rust code from the game logic chapter can now safely be copied, because the tiles variable is cloned in the previous step.
Fixes#5825Fixes#5824
The quickstart use the slint macro which doesn't use build.rs. The template is conter-productive
as it uses the slint-build and build.rs to compile Slint file.
If we're not using that, it is much easier to start with a fresh clean project.
