They should be in the lines, but the problem is that this causes issues
in the .mdx files.
License header doesn't really make sense for .md files anyway
We were missing some which had errors
Fixes#2689
(Although the error for 2689 was in C++ and would not have been
discovered by the test, better to have it parsed anyway)
After commit 3e5aa212d5 the Slint DLLs
aren't placed in the `bin/` directory by default anymore. Since the
tutorial builds Slint as an external sub-project, it is entirely
isolated and the CMAKE_*_OUTPUT_DIRECTORY variables do not propagate. On
macOS and Linux, the program still runs due to rpath. On Windows, the
instructions said to put `bin` into `%PATH%`, but that doesn't work
anymore, the dll is now in `_deps/slint-build`.
Instead of adjusting `%PATH%`, this change adjusts the documentation to
recommend the use of a custom command on Windows using
$<TARGET_RUNTIME_DLLS:tgt> to copy the DLL across. This is guarded with
WIN32 due to https://gitlab.kitware.com/cmake/cmake/-/issues/23543 ,
where the proposed solution requires CMake 3.26 (not released yet).
Also update a few more links and reference to slint in the readme
I know this means that we will have invalid links and instructions until the release,
but the instructions are already broken anyway
