Remove code comment (#4857)

src/absil/illib.fs

@@ -1145,7 +1145,6 @@ module MultiMap =
     let find v (m: MultiMap<_,_>) = match Map.tryFind v m with None -> [] | Some r -> r
     let add v x (m: MultiMap<_,_>) = Map.add v (x :: find v m) m
     let range (m: MultiMap<_,_>) = Map.foldBack (fun _ x sofar -> x @ sofar) m []
-    //let chooseRange f (m: MultiMap<_,_>) = Map.foldBack (fun _ x sofar -> List.choose f x @ sofar) m []
     let empty : MultiMap<_,_> = Map.empty
     let initBy f xs : MultiMap<_,_> = xs |> Seq.groupBy f |> Seq.map (fun (k,v) -> (k,List.ofSeq v)) |> Map.ofSeq