Porting note:
Following the discussion on [Zulip](https://leanprover.zulipchat.com/#narrow/stream/287929-
mathlib4/topic/porting.20.60.2Earray.60.20files.20whose.20PR's.20were.20closed.3F), these
will wait until Std4 has finalized DArray
and Array'
types so we can translates
apples to apples.
align
for lemmas about lean3/mathlib3 versions of d_array and array with mathport output