[Agda] decidable _∈_

[Sergei Meshveliani]

People,
I write
         _∈?_ x =  Data.List.Any.any (_≟_ x)

for the decidable list membership.
But may be Standard library needs to have this   
                                  _∈_ : (x : A) → Decidable (_∈_ x)
?

Thanks,

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Sergei