Correctly detect elements coming from different realms

This does not support elements coming from a third realm, different from the one we are running and the one the document belongs to, but this is even less common than having to deal with crossrealm elements to begin with. (And impossible on Firefox)

src/registry.ts

@@ -83,7 +83,11 @@ export default class Registry implements RegistryInterface {
       } else if (query & Scope.LEVEL & Scope.INLINE) {
         match = this.types.inline;
       }
-    } else if (query instanceof Element) {
+    } else if (
+      query instanceof HTMLElement ||
+      query instanceof
+        (query.ownerDocument?.defaultView?.HTMLElement ?? HTMLElement)
+    ) {
       const names = (query.getAttribute('class') || '').split(/\s+/);
       names.some((name) => {
         match = this.classes[name];