[Constraints] Fixed incosistenties and reordered config blocks

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | -

I planned to do a config block reorder PR, but before that, I just want to know what you think about this. This PR reordered the configuration blocks in the constraints reference and fixes some other issues with the examples.

If you think it is good to recheck the order of all configuration blocks in the docs, we should think of the best order. In general, it will be `yaml, [annotations,] xml, php`, but in the big bundles, you see that xml is used a lot for service configuration, we should maybe have a `xml, yaml, php` order there.

 > PS: I don't start with the next PR about this topic soon, let's document important features first! :blue_book: