AK: Make NonnullRefPtrVector constructible from Vector<NonnullRefPtr>

Author: https://github.com/alimpfard
Commit: https://github.com/SerenityOS/serenity/commit/7b2c8381623
Pull-request: https://github.com/SerenityOS/serenity/pull/7977
Reviewed-by: https://github.com/awesomekling

AK/NonnullRefPtrVector.h

@@ -13,6 +13,7 @@ namespace AK {
 
 template<typename T, size_t inline_capacity>
 class NonnullRefPtrVector : public NonnullPtrVector<NonnullRefPtr<T>, inline_capacity> {
+    using NonnullPtrVector<NonnullRefPtr<T>, inline_capacity>::NonnullPtrVector;
 };
 
 }