fix err msg wrapping

mc_openapi/assets/templates/error.html

@@ -11,7 +11,7 @@
     </div>
     <div class="message-body">
         <h2 class="title is-6 my-2">Description</h2>
-        <p>{{message}}</p>
+        <pre class="is-family-monospace message-body">{{message}}</pre>
         <details>
             <summary class="title is-6 my-2">Debug Message</summary>
             <pre class="is-family-monospace message-body">