deleteat!(::BitVector, inds) : check bounds for the first passed index

[rfourquet]

Similar to #36231, a discourse post about this method just prompted me to check whether this also needed fixing, it does:

julia> deleteat!(trues(1), [2])
0-element BitArray{1}

julia> deleteat!(trues(1), [-1, 0, 1])
0-element BitArray{1}:

julia> deleteat!(trues(1), [-1, 1]) # this one correctly throws for some reason
ERROR: BoundsError: attempt to access 1-element Array{UInt64,1} at index [0]
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