Issue #2019123 by klausi, ygerasimov, Crell: Use the same canonical URI paths as for HTML routes.

core/core.services.yml

...lib/Drupal/Core/EventSubscriber/RouteMethodSubscriber.php

core/lib/Drupal/Core/Routing/AcceptHeaderMatcher.php

core/lib/Drupal/Core/Routing/ContentTypeHeaderMatcher.php

...st/lib/Drupal/rest/Plugin/Derivative/EntityDerivative.php

core/modules/rest/lib/Drupal/rest/Plugin/ResourceBase.php

...st/lib/Drupal/rest/Plugin/rest/resource/DBLogResource.php

...t/lib/Drupal/rest/Plugin/rest/resource/EntityResource.php

core/modules/rest/lib/Drupal/rest/RequestHandler.php

core/modules/rest/lib/Drupal/rest/Tests/AuthTest.php

core/modules/rest/lib/Drupal/rest/Tests/DeleteTest.php

core/modules/rest/lib/Drupal/rest/Tests/NodeTest.php

core/modules/rest/lib/Drupal/rest/Tests/RESTTestBase.php

core/modules/rest/lib/Drupal/rest/Tests/ReadTest.php

core/modules/rest/lib/Drupal/rest/Tests/ResourceTest.php

core/modules/rest/lib/Drupal/rest/Tests/UpdateTest.php

...s/system/lib/Drupal/system/PathBasedBreadcrumbBuilder.php

...sts/Drupal/Tests/Core/Routing/AcceptHeaderMatcherTest.php

...rupal/Tests/Core/Routing/ContentTypeHeaderMatcherTest.php

core/tests/Drupal/Tests/Core/Routing/RoutingFixtures.php