Four sites already on main that `cargo xtask ci` cannot get past with the
current toolchain; each rewrite is the one clippy suggests and changes no
behaviour. `!x.is_some_and(f)` becomes `x.is_none_or(!f)`, and pdf_bounds
folds `!(a && b) || !c` into `!(a && b && c)` by De Morgan.
Unrelated to the merge they are committed beside; separated so that merge
stays a merge.