Add trailing newline

domains/404.json

@@ -6,4 +6,4 @@
     "A": ["185.199.108.153", "185.199.109.153", "185.199.110.153", "185.199.111.153"],
     "TXT": ["_github-pages-challenge-audtjddld.404.is-a.dev=56294933a979f0aed3b984ebf5f686"]
   }
-}
+}