Replace `Set UnitId` with `UniqDSet UnitId`
Continuing from #22426, we should also replace usages of Set UnitId
with the more specialised UniqDSet
instead.
As with Data.Map
, the use of Data.Set
results in lexicalCompareFS
being called in the Ord UnitId
instance. By instead using UniqDSet
, the comparisons will be replaced by fast Int
comparisons.