Fix out of range issues with GetEnumerator

[Swoorup]

Fix the following exception:

let vec = Vec.ofArray [|1; 2; 3;|]
let s = seq { for i in vec do yield i }
s |> Seq.iter (printfn "%A")

System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at <StartupCode$Domain-Pls-FsUtil>.$Vec.System-Collections-Generic-IEnumerable<'a>[email protected]<'a>.get_Current() in /Users/swoorup.joshi/work/gp-pls-fsutil/src/Domain.Pls.FsUtil/Vec.fs:line 454

[Horusiath]

Hi @Swoorup, thanks for the fix. Could you attach a test case confirming that issue has been fixed?

[Swoorup]

@Horusiath done.