rustc_layout_scalar_valid_range_end does not affect niches

[Veykril]

Works properly has a niche of 1, while DoesNotWork has no niches even though it should

#[rustc_layout_scalar_valid_range_start(1)]
pub struct Works {
  private: u32,
}
#[rustc_layout_scalar_valid_range_end(0xFFFF_FF00)]
pub struct DoesNotWork {
  private: u32,
}

[Veykril]

ah the problem is the hex number