Lint

[ustulation]

Bring back the bad_style lint (previously in forbid section and needed to be removed due to serde) as deny and specifially allow the non-camel-case required by serde as in S.E for e.g.

[ustulation]

cc @nbaksalyar

[povilasb]

Now it's called nonstandard-style lint:

Additionally, there's a bad-style lint group that's a deprecated alias for nonstandard-style.

See https://doc.rust-lang.org/rustc/lints/groups.html