@API(status = API.Status.STABLE)
    public static <C> @NonNull ParserDescriptor<C, Boolean> booleanParser(final boolean liberal) {
        return ParserDescriptor.of(new BooleanParser<>(liberal), Boolean.class);
    }
Creates a new boolean parser. If {@code liberal} is {@code true} the parser only
accepts {@code true} and {@code false}.

@param <C>     the command sender type
@param liberal whether the parser should be liberal, see {@link CommandInput#isValidBoolean(boolean)}
@return the created parser
cloud-core/src/main/java/org/incendo/cloud/parser/standard/BooleanParser.java