Replace `allow` with `expect` lints for `unused`, `unsafe_code`,
`dead_code`, and `non_upper_case_globals`.
Testing: So far just check it compiled on `x86_64-linux` on NixOS. Need
to use the module `system.fontconfig.enable = true;` I think in my NixOS
config.
Part of: #40383
Searching `allow\(.*\)` for `.rs` files shows the following. for
(total_results:total_files) went from `707:386` to `675:368`, a
reduction of `32:18`.
How many files is too many files per PR? I feel like the 20-30 I have is
too big.
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Signed-off-by: Wayne Van Son <waynevanson@gmail.com>