Grammar nit

src/librustc_mir/transform/promote_consts.rs

@@ -333,8 +333,8 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
  mem::replace(&mut args[index], operand)
  }
  // We expected a `TerminatorKind::Call` for which we'd like to promote an
- // argument. Since `qualify_consts` saw a `TerminatorKind::Call` here, but
- // we are seeing a `Goto`, that means that the `promote_temps` method
+ // argument. `qualify_consts` saw a `TerminatorKind::Call` here, but
+ // we are seeing a `Goto`. That means that the `promote_temps` method
  // already promoted this call away entirely. This case occurs when calling
  // a function requiring a constant argument and as that constant value
  // providing a value whose computation contains another call to a function