Rollup merge of #89507 - lopopolo:lopopolo/ordering-repr-i8, r=joshtriplett
Rollup merge of #89507 - lopopolo:lopopolo/ordering-repr-i8, r=joshtriplett

Add `#[repr(i8)]` to `Ordering`

Followup to #89491 to allow `Ordering` to auto-derive `AsRepr` once the proposal to add `AsRepr` (#81642) lands.

cc ``@joshtriplett``

aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust