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/Loader/ContentFilter.cpp

@@ -15,13 +15,9 @@ ContentFilter& ContentFilter::the()
     return filter;
 }
 
-ContentFilter::ContentFilter()
-{
-}
+ContentFilter::ContentFilter() = default;
 
-ContentFilter::~ContentFilter()
-{
-}
+ContentFilter::~ContentFilter() = default;
 
 bool ContentFilter::is_filtered(const AK::URL& url) const
 {

Userland/Libraries/LibWeb/Loader/FrameLoader.cpp

@@ -36,9 +36,7 @@ FrameLoader::FrameLoader(HTML::BrowsingContext& browsing_context)
     }
 }
 
-FrameLoader::~FrameLoader()
-{
-}
+FrameLoader::~FrameLoader() = default;
 
 static bool build_markdown_document(DOM::Document& document, const ByteBuffer& data)
 {

Userland/Libraries/LibWeb/Loader/ImageResource.cpp

@@ -15,9 +15,7 @@ ImageResource::ImageResource(const LoadRequest& request)
 {
 }
 
-ImageResource::~ImageResource()
-{
-}
+ImageResource::~ImageResource() = default;
 
 int ImageResource::frame_duration(size_t frame_index) const
 {
@@ -97,8 +95,6 @@ void ImageResource::update_volatility()
     m_has_attempted_decode = false;
 }
 
-ImageResourceClient::~ImageResourceClient()
-{
-}
+ImageResourceClient::~ImageResourceClient() = default;
 
 }

Userland/Libraries/LibWeb/Loader/Resource.cpp

@@ -25,9 +25,7 @@ Resource::Resource(Type type, const LoadRequest& request)
 {
 }
 
-Resource::~Resource()
-{
-}
+Resource::~Resource() = default;
 
 void Resource::for_each_client(Function<void(ResourceClient&)> callback)
 {