LibWeb/CSS: Parse the & nesting selector

Author: https://github.com/AtkinsSJ
Commit: 5b4d1b5b05
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1842
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/Dump.cpp

@@ -503,6 +503,9 @@ void dump_selector(StringBuilder& builder, CSS::Selector const& selector, int in
             case CSS::Selector::SimpleSelector::Type::PseudoElement:
                 type_description = "PseudoElement";
                 break;
+            case CSS::Selector::SimpleSelector::Type::Nesting:
+                type_description = "Nesting";
+                break;
             }
 
             builder.appendff("{}:", type_description);