Fix tests + harmonize linked items on show pages

src/Domain/Registry/Model/Request.php

src/Domain/User/Controller/CollectivityController.php

templates/Registry/Contractor/show.html.twig

templates/Registry/Mesurement/show.html.twig

templates/Registry/Request/show.html.twig

templates/Registry/Tool/show.html.twig

templates/Registry/Treatment/show.html.twig

templates/Registry/Violation/show.html.twig

tests/Domain/Registry/Form/Type/MesurementTypeTest.php

tests/Domain/Registry/Form/Type/ProofTypeTest.php

tests/Domain/Registry/Form/Type/RequestTypeTest.php

tests/Domain/Registry/Form/Type/ToolTypeTest.php

tests/Domain/Registry/Form/Type/TreatmentTypeTest.php

tests/Domain/Registry/Form/Type/ViolationTypeTest.php