Make unknown links sorted at the bottom.

source/ts/utilities/relation-link.ts

@@ -18,6 +18,7 @@ const known: KnownLink[] = knownLinks.map((data: Record<string, unknown>) => ({
 }));
 
 export default class RelationLink {
+  public readonly isKnown: boolean;
   public readonly link: URL;
   public readonly original: string;
   public readonly text: string;
@@ -27,6 +28,7 @@ export default class RelationLink {
     this.link = new URL(relationUrl);
 
     const knownLink = known.find(({regex}) => regex.test(this.link.host));
+    this.isKnown = knownLink !== undefined;
     this.text = knownLink?.text ?? this.link.host;
   }
 }

source/ts/utilities/release.ts

@@ -58,7 +58,14 @@ export default class Release {
     );
     const links = Array.from(relations)
       .map((url) => new RelationLink(url))
-      .sort((a, b) => a.text.localeCompare(b.text));
+      .sort((a, b) =>
+        // Sort links that aren't known to us at the bottom.
+        a.isKnown === b.isKnown
+          ? a.text.localeCompare(b.text)
+          : b.isKnown
+          ? 1 // This return 1 or -1 is because .sort() expects a number.
+          : -1,
+      );
 
     return new Release({
       artist,