Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibWeb/DOMParsing/XMLSerializer.idl

@@ -0,0 +1,8 @@
+#import <DOM/Node.idl>
+
+// https://w3c.github.io/DOM-Parsing/#the-xmlserializer-interface
+[Exposed=Window]
+interface XMLSerializer {
+    constructor();
+    DOMString serializeToString(Node root);
+};