Clippy reports issues from generated code

[autarch]

If I run clippy against a crate that contains the module generated by icu4x-datagen I get a whole bunch of clippy errors. Here's a sample:

$> cargo clippy --locked --all-targets --all-features --workspace -- -D clippy::all

Checking omegasort-rs v0.1.0 (/home/autarch/projects/omegasort-rs)
error: module has the same name as its containing module
 --> src/./icu-data/mod.rs:2:1
  |
2 | mod collator ; mod fallback ; mod normalizer ; use :: icu_provider :: prelude :: * ; # [doc = r" Implement [`DataProvider<M>`] on the given str...
  | ^^^^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#module_inception
  = note: `-D clippy::module-inception` implied by `-D clippy::all`

error: unnecessary closure used with `bool::then`
 --> src/./icu-data/collator/jamo_v1/mod.rs:2:253
  |
2 | ... 'static DataStruct > { locale . is_empty () . then (|| & UND) } static UND : DataStruct = include ! ("und.rs.data") ;
  |                            ^^^^^^^^^^^^^^^^^^^^^^^---------------
  |                                                   |
  |                                                   help: use `then_some(..)` instead: `then_some(& UND)`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluations
  = note: `-D clippy::unnecessary-lazy-evaluations` implied by `-D clippy::all`

I note that the generated code has some #[allow (clippy :: octal_escapes)] bits in it, but that's not helping with this.

I think it'd be best to just #[allow(clippy)]. Otherwise every time clippy adds a new lint that causes a lint failure you need to update the icu4x-datagen crate and I need to regenerate the generated code.

[sffc]

CC @robertbastian

Separately: if you pass --pretty to icu4x-datagen, it will invoke rustfmt for you, which may help a bit in the readability of these warnings.

[robertbastian]

Hmm, yeah we should probably add #![allow(clippy::all)]. I do want to have clippy during development though.

[robertbastian]

I found the #[clippy::msrv] attribute which we can set. Note that your first clippy finding is actually due to how you named the enclosing module, and I think that's a valid point.