@SuppressWarnings("unchecked")
    @Override
    default @NonNull SuggestionProvider<C> suggestionProvider() {
        if (this instanceof SuggestionProvider) {
            return (SuggestionProvider<C>) this;
        }
        return SuggestionProvider.noSuggestions();
    }
Returns the suggestion provider.
<p>
By default, this will return the parser, if the parser is also a {@link SuggestionProvider}.
Otherwise, {@link SuggestionProvider#noSuggestions()} will be returned.

@return the suggestion provider
cloud-core/src/main/java/org/incendo/cloud/parser/ArgumentParser.java