message: Allow unused_extern_crates in generated code
  Summary: This is a warning that lalrpop generates, so allow the warning to be turned on.
diff: @@ -38,6 +38,7 @@ pub(crate) mod validate;
  #[allow(clippy::inefficient_to_string)]
  #[allow(clippy::trivially_copy_pass_by_ref)]
  #[allow(clippy::too_many_arguments)]
  +#[allow(unused_extern_crates)]
  #[cfg_attr(feature = "custom_linter", allow(gazebo_use_dupe))]
  mod grammar {
  include!(concat!(env!("OUT_DIR"), "/syntax/grammar.rs"));
  