Currently when running wally search only packages from within the immediate registry will be shown, however if a search query returns no results and the immediate registry has fallback registries then wally should attempt to search those registries too for results.

Not sure what the implications would be when it comes to fallback registry chains (would it only search the immediate fallback registries?) and whether wally should only search fallback registries if there are no results or if it should always search fallback registries for results that match the query.