Properly handle annotations everywhere in swayfmt

[ironcev]

There are cases in which swayfmt does not handle annotations at all, but just strips them away from the formatted code. One example would be stripping them from the last enum variant. Considering the upcoming language development, e.g. the ABI errors or derives, and the more prominent use of the cfg attribute for experimental features, having proper support for annotations everywhere in the swayfmt will become a necessity.