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/DOM/Text.h

@@ -17,7 +17,7 @@ public:
     using WrapperType = Bindings::TextWrapper;
 
     explicit Text(Document&, const String&);
-    virtual ~Text() override;
+    virtual ~Text() override = default;
 
     static NonnullRefPtr<Text> create_with_global_object(Bindings::WindowObject& window, String const& data);