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/History.cpp

@@ -14,9 +14,7 @@ History::History(DOM::Document& document)
 {
 }
 
-History::~History()
-{
-}
+History::~History() = default;
 
 // https://html.spec.whatwg.org/multipage/history.html#dom-history-pushstate
 DOM::ExceptionOr<void> History::push_state(JS::Value data, String const&, String const& url)