@SafeVarargs
	public static <T> Stream<T> chain(Supplier<Optional<T>>... suppliers) {
		return Arrays.stream(suppliers)
			.map(Supplier::get)
			.flatMap(o -> o.map(Stream::of).orElseGet(Stream::empty));
	}
Return ImplicitCatalogRef if can be parsed into a git accessible structure.

@param name
@return null if cannot parse it
src/main/java/dev/jbang/catalog/ImplicitCatalogRef.java