Changed API for SatisfiesM_mapIdxM.go

Stream: mathlib4

[Scott Morrison]

@Mario Carneiro, I got stuck updating the version of Std in mathlib4 at Data/Array/Basic.lean, following your change to the signature of SatisfiesM_mapIdxM.go yesterday. I suspect it is going to be much easier for you to fix this than me. Would you mind fixing the error in the branch bump_std?

[Mario Carneiro]

I think you can just delete that theorem. It was previously a lemma in another theorem which has since been moved to std