docs(rest): add German reference coverage

tests/test_rest_module_contract.py

@@ -24,6 +24,13 @@ class RestModuleContractTests(unittest.TestCase):
         self.assertEqual("/rest", router.prefix)
         self.assertEqual(1, len(router.routes))
 
+    def test_public_reference_has_complete_german_localization(self) -> None:
+        topic = get_manifest().documentation[0]
+        translation = topic.translations["de"]
+
+        self.assertEqual({"title", "summary", "body"}, set(translation))
+        self.assertTrue(all(str(translation[field]).strip() for field in translation))
+
     def test_function_descriptor_is_stable(self) -> None:
         descriptor = RestFunctionDescriptor(
             id="demo.ping",