uv

84846117 - Rename `Error::IO` to `Error::Io` (#5174)

Rename `Error::IO` to `Error::Io` (#5174) ## Summary I believe this is by convention (see, e.g., in Rust itself: https://github.com/search?q=repo%3Arust-lang%2Frust+%2F%28%3F-i%29Io%2F&type=code).