LibWeb: Add NestedHistory in DocumentState

Author: https://github.com/kalenikaliaksandr
Commit: 51d64bdaec
Pull-request: https://github.com/SerenityOS/serenity/pull/18541
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibWeb/HTML/DocumentState.cpp

@@ -18,6 +18,11 @@ void DocumentState::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(m_document);
+    for (auto& nested_history : m_nested_histories) {
+        for (auto& entry : nested_history.entries) {
+            visitor.visit(entry);
+        }
+    }
 }
 
 }