LibURL/Pattern: Complete the implementation of the constructor

Author: https://github.com/shannonbooth
Commit: e35555f00e
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3847
Reviewed-by: https://github.com/trflynn89

Libraries/LibURL/Pattern/Component.h

@@ -34,4 +34,6 @@ struct Component {
     static PatternErrorOr<Component> compile(Utf8View const& input, PatternParser::EncodingCallback, Options const&);
 };
 
+bool protocol_component_matches_a_special_scheme(Component const& protocol_component);
+
 }