style: format code with Prettier and RuboCop

This commit fixes the style issues introduced in de6ccc2 according to the output
from Prettier and RuboCop.

Details: #1163

_includes/head.html

@@ -13,13 +13,12 @@
   <meta
     name="description"
     content="Aggregate, curate, disseminate, and apply information derived from diverse sources." />
-<link
-  rel="stylesheet"
-  href="https://cdnjs.cloudflare.com/ajax/libs/normalize/8.0.1/normalize.min.css"
-  integrity="sha512-NhSC1YmyruXifcj/KFRWoC561YpHpc5Jtzgvbuzx5VozKpWvQ+4nXhPdFgmx8xqexRcpAglTj9sIBWINXa8x5w=="
-  crossorigin="anonymous"
-  referrerpolicy="no-referrer"
-/>
+  <link
+    rel="stylesheet"
+    href="https://cdnjs.cloudflare.com/ajax/libs/normalize/8.0.1/normalize.min.css"
+    integrity="sha512-NhSC1YmyruXifcj/KFRWoC561YpHpc5Jtzgvbuzx5VozKpWvQ+4nXhPdFgmx8xqexRcpAglTj9sIBWINXa8x5w=="
+    crossorigin="anonymous"
+    referrerpolicy="no-referrer" />
   <style>
     {%- include assets/css/main.css -%}
   </style>