message: Keep remaining clippy ignores
diff: #![feature(bool_to_option)]
  #![feature(io_error_more)]
  #![warn(rust_2018_idioms)]
  -#![allow(clippy::cast_lossless)]
  -// TODO: Uncategorized. Some of these we'll want to fix, some keep ignored.
  #![allow(
  + clippy::cast_lossless,
  clippy::collapsible_else_if,
  clippy::collapsible_if,
  clippy::comparison_chain,
  