LibWeb: Implement ChildNode.replaceWith

Author: https://github.com/Lubrsi
Commit: 7431f6073b
Pull-request: https://github.com/SerenityOS/serenity/pull/12208
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/DOM/CharacterData.idl

@@ -9,6 +9,7 @@ interface CharacterData : Node {
     // FIXME: These should come from a ChildNode mixin
     [CEReactions, Unscopable] undefined before((Node or DOMString)... nodes);
     [CEReactions, Unscopable] undefined after((Node or DOMString)... nodes);
+    [CEReactions, Unscopable] undefined replaceWith((Node or DOMString)... nodes);
     [CEReactions, Unscopable, ImplementedAs=remove_binding] undefined remove();
 
 };