Libraries: Use default constructors/destructors in LibWeb

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Libraries/LibWeb/HTML/HTMLObjectElement.cpp

@@ -35,9 +35,7 @@ HTMLObjectElement::HTMLObjectElement(DOM::Document& document, DOM::QualifiedName
     };
 }
 
-HTMLObjectElement::~HTMLObjectElement()
-{
-}
+HTMLObjectElement::~HTMLObjectElement() = default;
 
 void HTMLObjectElement::parse_attribute(const FlyString& name, const String& value)
 {