LibWeb: Implement 'host is domain' concept from the URL spec

Author: https://github.com/linusg
Commit: 7fd4c7b0c6
Pull-request: https://github.com/SerenityOS/serenity/pull/15795
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/davidot ✅

Userland/Libraries/LibWeb/URL/URL.h

@@ -72,5 +72,6 @@ private:
 };
 
 HTML::Origin url_origin(AK::URL const&);
+bool host_is_domain(StringView host);
 
 }