LibWeb: Add the ResizeObserverBoxOptions IDL enum

Author: https://github.com/IdanHo
Commit: 61fc3c31c6
Pull-request: https://github.com/SerenityOS/serenity/pull/13424
Reviewed-by: https://github.com/alimpfard ✅

Userland/Libraries/LibWeb/Forward.h

@@ -562,5 +562,6 @@ class XMLHttpRequestPrototype;
 class XMLHttpRequestWrapper;
 enum class CanPlayTypeResult;
 enum class DOMParserSupportedType;
+enum class ResizeObserverBoxOptions;
 enum class XMLHttpRequestResponseType;
 }