Add a link to the MusicBrainz release (#8).

source/scss/pages/_release.scss

@@ -37,6 +37,10 @@
   .no-links {
     text-align: center;
   }
+
+  .divider {
+    border-top: 2px solid var(--background-1);
+  }
 }
 
 .release-link {

source/ts/pages/release.ts

@@ -80,8 +80,9 @@ export default class ReleasePage extends Component<Props, State> {
           `,
       );
 
+      const releaseUrl = `https://musicbrainz.org/release/${mbid}`;
       if (urls.length === 0) {
-        const editUrl = `https://musicbrainz.org/release/${mbid}/edit`;
+        const editUrl = `${releaseUrl}/edit`;
         urls.push(
           html`
             <li class="no-links">
@@ -92,6 +93,15 @@ export default class ReleasePage extends Component<Props, State> {
             </li>
           `,
         );
+      } else {
+        urls.push(
+          html`<li class="divider"></li>`,
+          html`
+            <li class="release-link">
+              <${ExternalAnchor} url="${releaseUrl}" text="MusicBrainz" />
+            </li>
+          `,
+        );
       }
 
       return html`